0000911177-24-000005 | 10-K | XBRL Viewer | Casella Waste Systems INC

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PROPERTY AND EQUIPMENT - Narrative (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 99,249	$ 78,139	$ 62,342
Landfills
Property, Plant and Equipment [Line Items]
Amortization expense	$ 40,419	$ 31,619	$ 30,295

RELATED PARTY TRANSACTIONS	12 Months Ended
RELATED PARTY TRANSACTIONS	Dec. 31, 2023
Related Party Transactions [Abstract]
RELATED PARTY TRANSACTIONS	RELATED PARTY TRANSACTIONS Services During fiscal years 2023, 2022 and 2021, we retained the services of Casella Construction, Inc. ("CCI"), a company substantially owned by sons of John Casella, our Chairman and Chief Executive Officer, and Douglas Casella, a member of our Board of Directors, as a contractor in developing or closing certain landfills owned by us as well as providing transportation and construction services. Total purchased services charged to operations or capitalized to landfills for fiscal years 2023, 2022 and 2021 were $7,682, $12,297 and $15,206, respectively, of which $595 and $1,891 were outstanding and included in either accounts payable or other current liabilities as of December 31, 2023 and December 31, 2022, respectively. In addition to the total purchased services, we provided various waste collection and disposal services to CCI. Total revenues recorded for fiscal years 2023, 2022 and 2021 were $241, $141 and $430, respectively. Leases In the fiscal year ended April 30, 1994, we entered into two leases for operating facilities with a partnership of which John Casella, our Chairman and Chief Executive Officer, and Douglas Casella, a member of our Board of Directors, are the general partners. The leases have since been extended through August 2023 and have since continued on a month-to-month basis. The terms of the lease agreements require monthly payments of approximately $29. Total expense charged to operations for fiscal years 2023, 2022 and 2021 under these agreements was $284, $273 and $297, respectively. Landfill Post-closure We have agreed to pay the cost of post-closure on a landfill owned by John Casella, our Chairman and Chief Executive Officer, and Douglas Casella, a member of our Board of Directors. We paid the cost of closing this landfill in 1992, and the post-closure maintenance obligations are expected to last until notified by the permitting authority. In fiscal years 2023, 2022 and 2021, we paid $3, $10 and $12, respectively, pursuant to this agreement. As of December 31, 2023 and December 31, 2022, we have accrued $17 and $17, respectively, for costs associated with its post-closure obligations.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Management’s Estimates and Assumptions

Preparation of our consolidated financial statements in accordance with GAAP requires management to make certain estimates and assumptions. These estimates and assumptions affect the accounting for and recognition and disclosure of assets, liabilities, equity, revenues and expenses. We must make these estimates and assumptions because certain information that we use is dependent on future events, cannot be calculated with a high degree of precision given the available data or simply cannot be readily calculated. In some cases, these estimates are difficult to determine, and we must exercise significant judgment. In preparing our consolidated financial statements, the estimates and assumptions that we consider to be significant and that present the greatest amount of uncertainty relate to our accounting for landfills, environmental remediation liabilities, asset impairments, if applicable, goodwill recoverability assessment, accounts receivable valuation allowance for credit losses, self-insurance reserves, deferred taxes and uncertain tax positions, estimates of the fair values of assets acquired and liabilities assumed in any acquisition, contingent liabilities and stock-based compensation. Each of these items is discussed in more detail elsewhere in these notes to the consolidated financial statements, as applicable. Actual results may differ materially from the estimates and assumptions that we use in the preparation of our consolidated financial statements.

Cash and Cash Equivalents

We consider all highly liquid investments purchased with original maturities of three months or less to be cash equivalents.

Concentrations of Credit Risk

Financial instruments that potentially subject us to concentrations of credit risk consist of cash and cash equivalents, restricted investment securities, accounts receivable and derivative instruments. We maintain cash and cash equivalents and restricted investment securities with banks that at times exceed applicable insurance limits. We reduce our exposure to credit risk by maintaining such deposits with high quality financial institutions. Our concentration of credit risk with respect to accounts receivable is limited because of the large number and diversity of customers we serve, thus reducing the credit risk associated with any one customer group. As of December 31, 2023, no single customer or customer group represented greater than 5% of total accounts receivable. We manage credit risk through credit evaluations, credit limits, and monitoring procedures, but generally do not require collateral to support accounts receivable. We reduce our exposure to credit risk associated with derivative instruments by entering into agreements with high quality financial institutions and by evaluating and regularly monitoring their creditworthiness.

Accounts Receivable, Net of Allowance for Credit Losses

Accounts receivable represent receivables from customers for collection, transfer, recycling, disposal and other services. Our accounts receivable are recorded when billed or when related revenue is earned, if earlier, and represent claims against third-parties that will be settled in cash. The carrying value of our accounts receivable, net of allowance for credit losses represents its estimated net realizable value. Estimates are used in determining our allowance for credit losses based on, among other things, our historical loss trends, the age of outstanding accounts receivable, and current and expected economic conditions. Our reserve is evaluated and revised on a monthly basis. Past due accounts receivable are written off when deemed to be uncollectible. See Note 6, Accounts Receivable, Net of Allowance for Credit Losses for disclosure over allowance for credit losses.

Inventory

Inventory includes secondary fibers, recyclables ready for sale, and parts and supplies. Inventory is stated at the lower of cost (first-in, first-out) or market.

Property and Equipment

Property and equipment is recorded at cost, less accumulated depreciation and amortization. We provide for depreciation and amortization using the straight-line method by charges to operations in amounts that allocate the cost of the assets over their estimated useful lives as follows:


Asset Classification						Estimated Useful Life
Buildings and improvements						10-30 years
Machinery and equipment						5-10 years
Rolling stock						5-10 years
Containers						5-12 years
Furniture and Fixtures						3-8 years

The cost of maintenance and repairs is charged to operations as incurred.

Landfill development costs are included in property and equipment. Landfill development costs include costs to develop each of our landfill sites, including such costs related to landfill liner material and installation, excavation for airspace, landfill leachate collection systems, landfill gas collection systems, environmental monitoring equipment for groundwater and landfill gas, directly related engineering, capitalized interest, on-site road construction, and other capital infrastructure. Additionally, landfill development costs include all land purchases within the landfill footprint and the purchase of any required landfill buffer property. Under life-cycle accounting, these costs are capitalized and charged to expense based on tonnage placed into each site. See the “Landfill Accounting” accounting policy below for additional disclosure about the amortization of landfill development costs and Note 7, Property and Equipment for disclosure about property and equipment.

Landfill Accounting

Life Cycle Accounting

Under life-cycle accounting, all costs related to acquisition and construction of landfill sites are capitalized and charged to expense based on tonnage placed into each site. Landfill permitting, acquisition and preparation costs are amortized on the units-of-consumption method as landfill airspace is consumed. In determining the amortization rate for each of our landfills, preparation costs include the total estimated costs to complete construction of the landfills’ permitted and expansion capacity.

Landfill Development Costs

We estimate the total cost to develop each of our landfill sites to its remaining permitted and expansion capacity (see landfill development costs discussed within the “Property and Equipment” accounting policy above). The projection of these landfill costs is dependent, in part, on future events. The remaining amortizable basis of each landfill includes costs to develop a site to its remaining permitted and expansion capacity and includes amounts previously expended and capitalized, net of accumulated airspace amortization, and projections of future purchase and development costs including capitalized interest. The interest capitalization rate is based on our weighted average interest rate incurred on borrowings outstanding during the period. Interest capitalized during the fiscal years ended December 31, 2023 ("fiscal year 2023"), December 31, 2022 ("fiscal year 2022") and December 31, 2021 ("fiscal year 2021") was $643, $330 and $718, respectively.

Landfill Airspace

We apply the following guidelines in determining a landfill’s remaining permitted and expansion airspace:

Remaining Permitted Airspace. Our engineers, in consultation with third-party engineering consultants and surveyors, are responsible for determining remaining permitted airspace at our landfills. The remaining permitted airspace is determined by an annual survey, which is then used to compare the existing landfill topography to the expected final landfill topography.

Expansion Airspace. We currently include unpermitted expansion airspace in our estimate of remaining permitted and expansion airspace in certain circumstances. To be considered expansion airspace all of the following criteria must be met:

•we control the land on which the expansion is sought;

•all technical siting criteria have been met or a variance has been obtained or is reasonably expected to be obtained;

•we have not identified any legal or political impediments which we believe will not be resolved in our favor;

•we are actively working on obtaining any necessary permits and we expect that all required permits will be received; and

•senior management has approved the project based on a review of the engineering design and determination that the financial return profile meets our investment criteria.

For unpermitted airspace to be included in our estimate of remaining permitted and expansion airspace, the expansion effort must meet all of the criteria listed above. These criteria are evaluated annually by our engineers, accountants, lawyers, managers and others to identify potential obstacles to obtaining the permits. Once the remaining permitted and expansion airspace is determined in cubic yards, an airspace utilization factor (“AUF”) is established to calculate the remaining permitted and expansion capacity in tons. The AUF is established using a process that considers the measured density obtained from annual surveys. When we include the expansion airspace in our calculation of remaining permitted and expansion airspace, we include the projected costs for development, as well as the projected asset retirement costs related to final capping, closure and post-closure of the expansion airspace in the amortization basis of the landfill.

After determining the costs and the remaining permitted and expansion capacity at each of our landfills, we determine the per ton rates that will be expensed as waste is received and deposited at each of our landfills by dividing the costs by the corresponding number of tons. We calculate per ton amortization rates for assets associated with each final capping event, for assets related to closure and post-closure activities, and for all other costs capitalized or to be capitalized in the future for each landfill. These rates per ton are updated annually, or more frequently, as significant facts change.

It is possible that actual results, including the amount of costs incurred, the timing of final capping, closure and post-closure activities, our airspace utilization or the success of our expansion efforts, could ultimately turn out to be significantly different from our estimates and assumptions. To the extent that such estimates or related assumptions prove to be significantly different than actual results, lower profitability may be experienced due to higher amortization rates, higher final capping, closure or post-closure rates, or higher expenses. Higher profitability may result if the opposite occurs. Most significantly, if it is determined that the expansion capacity should no longer be considered in calculating the recoverability of the landfill asset, we may be required to recognize an asset impairment. If it is determined that the likelihood of receiving an expansion permit has become remote, the capitalized costs related to the expansion effort are expensed immediately.

Final Capping, Closure and Post-Closure Costs

The following is a description of our landfill asset retirement activities and related accounting:

Final Capping Costs. Final capping activities include the installation of liners, drainage, compacted soil layers and topsoil over areas of a landfill where total airspace has been consumed and waste is no longer being received. Final capping activities occur throughout the life of the landfill. Our engineering personnel estimate the cost for each final capping event based on the acreage to be capped, along with the final capping materials and activities required. The estimates also consider when these costs would actually be paid and factor in inflation and discount rates. The engineers then quantify the landfill capacity associated with each final capping event and the costs for each event are amortized over that capacity as waste is received at the landfill.

Closure and Post-Closure Costs. Closure and post-closure costs represent future estimated costs related to monitoring and maintenance of a solid waste landfill after a landfill facility ceases to accept waste and closes. We estimate, based on input from our engineers, accountants, lawyers, managers and others, our future cost requirements for closure and post-closure monitoring and maintenance based on our interpretation of the technical standards of the Subtitle D regulations and the air emissions standards under the Clean Air Act of 1970, as amended, as they are being applied on a state-by-state basis. Closure and post-closure accruals for the cost of monitoring and maintenance include site inspection, groundwater monitoring, leachate management, methane gas control and recovery, and operation and maintenance costs to be incurred for a period which is generally for a term of 30 years after final closure of a landfill. In determining estimated future closure and post-closure costs, we consider costs associated with permitted and permittable airspace.

Our estimated future final capping, closure and post-closure costs, based on our interpretation of current requirements and proposed regulatory changes, are intended to approximate fair value. Absent quoted market prices, our cost estimates are based on historical experience, professional engineering judgment and quoted or actual prices paid for similar work. Our estimate of costs to discharge final capping, closure and post-closure asset retirement obligations for landfills are developed in today’s dollars. These costs are then inflated to the period of performance using an estimate of inflation, which is updated annually (2.4% as of December 31, 2023). Final capping, closure and post-closure liabilities are then discounted using the credit adjusted risk-free rate in effect at the time the obligation is incurred. The weighted average rate applicable to our asset retirement obligations as of December 31, 2023 is between approximately 6.1% and 10.0%, the range of the credit adjusted risk free rates effective since the adoption of guidance associated with asset retirement obligations in the fiscal year ended April 30, 2004. Accretion expense is necessary to increase the accrued final capping, closure and post-closure liabilities to the future anticipated obligation. To accomplish this, we accrete our final capping, closure and post-closure accrual balances using the same credit-adjusted risk-free rate that was used to calculate the recorded liability. Accretion expense on recorded landfill liabilities is recorded to cost of operations from the time the liability is recognized until the costs are paid. Accretion expense on recorded landfill liabilities amounted to $9,529, $7,565 and $6,775 in fiscal years 2023, 2022 and 2021, respectively.

We provide for the accrual and amortization of estimated future obligations for closure and post-closure based on tonnage placed into each site. With regards to final capping, the liability is recognized, and the costs are amortized based on the remaining airspace related to the specific final capping event. See Note 10, Final Capping, Closure and Post-Closure Costs for disclosure about asset retirement obligations related to final capping, closure and post-closure costs and Note 18, Other Items and Charges for disclosure about the write-off of historical payments for capping work associated with a veneer failure at a Subtitle D landfill we operate located in Seneca, New York ("Ontario County Landfill").

We operate in states which require a certain portion of landfill final capping, closure and post-closure obligations to be secured by financial assurance, which may take the form of surety bonds, letters of credit and restricted investment securities. Surety bonds securing closure and post-closure obligations at December 31, 2023 and December 31, 2022 totaled $241,728 and $231,871, respectively. There are no letters of credit securing closure and post-closure obligations as of December 31, 2023 and December 31, 2022. See Note 15, Fair Value of Financial Instruments for disclosure about restricted investment securities securing closure and post-closure obligations.

Lease Accounting

We lease vehicles, equipment, property and other non-core equipment in the ordinary course of our business. Leases are classified as either operating leases or finance leases, as appropriate. Our leases have varying terms and may include renewal or purchase options, escalation clauses, restrictions, lease concessions, capital project funding, penalties or other obligations that we consider in determining minimum rental payments. We recognize lease expense for operating leases on a straight-line basis over the lease term. We recognize depreciation expense for finance leases over either the useful life of the asset or the lease term based on the terms of the lease agreement.

We are also party to three landfill operation and management agreements that we account for as operating leases. These agreements are long-term landfill operating contracts with government bodies whereby we receive tipping revenue, pay normal operating expenses and assume future final capping, closure and post-closure obligations. The government bodies retain ownership of each landfill. There are no bargain purchase options and title to each of the properties does not pass to us at the end of the respective lease terms. We allocate the consideration paid to the landfill airspace rights and underlying land lease based on the relative fair values.

In addition to up-front or one-time payments, the landfill operating agreements may require us to make future minimum rental payments, including success or expansion fees, other direct costs and final capping, closure and post-closure costs. The value of all future minimum rental payments is amortized and charged to cost of operations over the life of the contract. We amortize the consideration allocated to airspace rights as airspace is utilized on a units-of-consumption basis and such amortization is charged to cost of operations as airspace is consumed (e.g., as tons are placed into the landfill). The underlying value of any land lease is amortized to cost of operations on a straight-line basis over the estimated life of the respective operating agreement.

We recognize a right-of-use asset and a lease liability for core leases classified as operating leases with a term in excess of 12 months in our consolidated balance sheets. For other non-core operating leases, which are comprised of small-dollar-value items such as office equipment, we expense these costs in the period incurred rather than capitalizing such expenditures on our consolidated balance sheets. We identify lease and nonlease components in a contract to which consideration in the contract will be allocated. We may elect by class of underlying asset to choose not to separate nonlease components from lease components and instead account for each separate lease component and the nonlease components in a contract as part of the single lease component. We have elected to not separate lease components from nonlease components for property leases and are, therefore, not allocating consideration between lease and nonlease components for this asset class. Lease payments include: fixed payments, including in-substance fixed payments, less any lease incentives paid or payable to the lessee; variable lease payments that depend on an index or a rate; exercise price of a purchase option reasonably certain to be exercised; penalties for terminating a lease; and amounts where it is probable that we will owe under a residual value guarantee. Refundable deposits are not considered to be a fixed payment. Variable lease costs that are not based on an index or a rate are recorded to expense in the period incurred. Lease term is determined at lease commencement and includes any noncancellable period for which we have the right to use the underlying asset together with any periods covered by an option to extend or terminate the lease if we are reasonably certain to exercise the option to extend or not to exercise the option to terminate. The initial determination of a lease liability is calculated as the net present value of the lease payments not yet paid. The discount rate used to determine present value is the rate implicit in the lease, if present, or, if not present, our incremental borrowing rate, which is a rate that reflects interest that we would have to pay to borrow funds on a collateralized basis over a similar term to the lease and in a similar economic environment. For shorter term leases, such as vehicle and equipment leases, we calculate our incremental borrowing rate using the interest rate from our existing secured line of credit, adjusted based on term. For longer term leases, such as our landfill operating leases, we calculate our incremental borrowing rate based on an industry yield curve with a similar credit rating, adjusted by a company specific spread as determined by a third-party. See Note 8, Leases for further disclosure about lease costs and other lease information.

Goodwill and Intangible Assets

Goodwill. Goodwill is the excess of our purchase consideration over the fair value of the net assets of acquired businesses. We do not amortize goodwill, but as discussed in the “Asset Impairments” accounting policy below, we assess our goodwill for impairment at least annually. See Note 9, Goodwill and Intangible Assets for disclosure about goodwill.

Intangible Assets. Intangible assets consist primarily of covenants not-to-compete, customer relationships, and trade names. Intangible assets are recorded at fair value and are amortized based on the economic benefit provided or using the sum of years digits or straight-line methods over their estimated useful lives. Covenants not-to-compete, customer relationships and trade names are typically amortized over a term of no more than 10 years. See Note 9, Goodwill and Intangible Assets for disclosure about intangible assets.

Investments in Unconsolidated Entities

Investments in unconsolidated entities over which we have significant influence over the investees’ operating and financing activities are accounted for under the equity method of accounting. As of December 31, 2023 and December 31, 2022, we had no investments accounted for under the equity method of accounting. Investments in affiliates in which we do not have the ability to exert significant influence over the investees’ operating and financing activities are accounted for under the cost method of accounting. As of December 31, 2023 and December 31, 2022, we had cost method investments totaling $10,967 and $10,967, respectively.

We monitor and assess the carrying value of our investments throughout the year for potential impairment and write them down to their fair value when other-than-temporary declines exist. Fair value is generally based on: (i) other third-party investors’ recent transactions in the securities; (ii) other information available regarding the current market for similar assets; and/or (iii) a market or income approach, as deemed appropriate.

When we assess the carrying value of our investments for potential impairment, determining the fair value of our investments is reliant upon the availability of market information and/or other information provided by third-parties to be able to develop an estimate of fair value. Considerable judgment is required in interpreting market data to develop the estimates of fair value. Accordingly, our estimates are not necessarily indicative of the amounts that we, or other holders of these investments, could realize in a current market exchange. The use of different assumptions and/or estimation methodologies could have a significant effect on the estimated fair values. The estimates of fair value could differ significantly from the amounts presented. See “Asset Impairments” accounting policy below.

Fair Value of Financial Instruments

Our financial instruments may include cash and cash equivalents, accounts receivable, restricted investment securities held in trust on deposit with various banks as collateral for our obligations relative to our landfill final capping, closure and post-closure costs, interest rate derivatives, contingent consideration related to acquisitions, trade payables and debt. Accounting standards include disclosure requirements around fair values used for certain financial instruments and establish a fair value hierarchy. The three-tier hierarchy prioritizes valuation inputs into three levels based on the extent to which inputs used in measuring fair value are observable in the market. Each fair value measurement is reported in one of three levels: Level 1, defined as quoted market prices in active markets for identical assets or liabilities; Level 2, defined as inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; and Level 3, defined as unobservable inputs that are not corroborated by market data. See Note 12, Debt and Note 15, Fair Value of Financial Instruments for fair value disclosure about debt and financial instruments, respectively. See the “Derivatives and Hedging” accounting policy below for the fair value disclosure about interest rate derivatives.

Business Combinations

We acquire businesses in the waste industry, including non-hazardous waste collection, transfer station, recycling and disposal operations, as part of our growth strategy. Businesses are included in the consolidated financial statements from the date of acquisition.

We recognize, separately from goodwill, the identifiable assets acquired and liabilities assumed at their estimated acquisition-date fair values. We measure and recognize goodwill as of the acquisition date as the excess of: (a) the aggregate of the fair value of consideration transferred, the fair value of any noncontrolling interest in the acquiree (if any) and the acquisition date fair value of our previously held equity interest in the acquiree (if any), over (b) the fair value of net assets acquired and liabilities assumed. If information about facts and circumstances existing as of the acquisition date is incomplete by the end of the reporting period in which a business combination occurs, we will report provisional amounts for the items for which the accounting is incomplete. The measurement period ends once we receive the information we were seeking; however, this period will not extend beyond one year from the acquisition date. Any material adjustments recognized during the measurement period will be recognized in the consolidated financial statements in the reporting period in which the adjustment amounts are determined. All acquisition-related transaction and restructuring costs are to be expensed as incurred. See Note 5, Business Combinations and Note 18, Other Items and Charges for disclosure about business acquisitions and acquisition related expense, respectively.

Environmental Remediation Liabilities

We have recorded environmental remediation liabilities representing our estimate of the most likely outcome of the matters for which we have determined that a liability is probable. These liabilities include potentially responsible party investigations, settlements, certain legal and consultant fees, as well as costs directly associated with site investigation and clean up, such as materials and incremental internal costs directly related to the remedy. We provide for expenses associated with environmental remediation obligations when such amounts are probable and can be reasonably estimated. We estimate costs required to remediate sites where it is probable that a liability has been incurred based on site-specific facts and circumstances. Estimates of the cost for the likely remedy are developed using third-party environmental engineers or other service providers. Where we believe that both the amount of a particular environmental remediation liability and timing of payments are reliably determinable, we inflate the cost in current dollars until the expected time of payment and discount the cost to present value. See Note 13, Commitments and Contingencies for disclosure about environmental remediation liabilities.

Self-Insurance Liabilities and Related Costs

We are self-insured for vehicles and workers’ compensation with reinsurance coverage limiting our maximum exposure. In fiscal year 2023, our maximum exposure per individual event under the workers’ compensation plan was $1,250. In fiscal year 2023, our minimum and maximum exposure per individual event under the automobile plan were up to $1,750 and $3,875, respectively. The liability for unpaid claims and associated expenses, including incurred but not reported losses, is determined by management with the assistance of a third-party actuary and reflected in our consolidated balance sheets as an accrued liability. We use a third-party to track and evaluate actual claims experience for consistency with the data used in the annual actuarial valuation. The actuarial-determined liability is calculated based on historical data, which considers both the frequency and settlement amount of claims. Our self-insurance reserves totaled $22,427 and $22,184 as of December 31, 2023 and December 31, 2022, respectively. Our estimated accruals for these liabilities could be significantly different than our ultimate obligations if variables such as the frequency or severity of future events differ significantly from our assumptions.

Income Taxes

We use estimates to determine our provision for income taxes and related assets and liabilities and any valuation allowance recorded against our net deferred tax assets. Valuation allowances have been established for the possibility that tax benefits may not be realized for certain deferred tax assets. Deferred income taxes are recognized based on the expected future tax consequences of differences between the financial statement basis and the tax basis of assets and liabilities, calculated using currently enacted tax rates. We record net deferred tax assets to the extent we believe these assets will more likely than not be realized. In making this determination, we consider all available positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax planning strategies and recent financial operations. In the event we determine that we would be able to realize our deferred income tax assets in the future in excess of their net recorded amount, we will make an adjustment to the valuation allowance which would reduce the provision for income taxes.

We account for income tax uncertainties according to guidance on the recognition, derecognition and measurement of potential tax benefits associated with tax positions. We recognize interest and penalties relating to income tax matters as a component of income tax expense. See Note 17, Income Taxes for disclosure related to income taxes.

Derivatives and Hedging

We account for derivatives and hedging activities in accordance with derivatives and hedging accounting guidance that establishes accounting and reporting standards requiring that every derivative instrument (including certain derivative instruments embedded in other contracts) be recorded in the consolidated balance sheet as either an asset or liability measured at its fair value. The guidance requires that changes in the derivative’s fair value be recognized currently in earnings unless specific hedge accounting criteria are met.

Our strategy to reduce exposure to interest rate risk involves entering into interest rate derivative agreements to hedge against adverse movements in interest rates related to the variable rate portion of our long-term debt. We have designated these derivative instruments as highly effective cash flow hedges, and therefore the change in their fair value is recorded in stockholders’ equity as a component of accumulated other comprehensive income (loss), net of tax and included in interest expense at the same time as interest expense is affected by the hedged transactions. Differences paid or received over the life of the agreements are recorded as additions to or reductions of interest expense on the underlying debt and included in cash flows from operating activities. See Note 12, Debt for further disclosure about interest rate derivatives and Note 15, Fair Value of Financial Instruments for fair value disclosure about derivative instruments.

Contingent Liabilities

We are subject to various legal proceedings, claims and regulatory matters, the outcomes of which are subject to significant uncertainty. We determine whether to disclose or accrue for loss contingencies based on an assessment of whether the risk of loss is remote, reasonably possible or probable, and whether it can be reasonably estimated. We analyze our litigation and regulatory matters based on available information to assess the potential liabilities. Management’s assessment is developed based on an analysis of possible outcomes under various strategies. We accrue for loss contingencies when such amounts are probable and reasonably estimable. If a contingent liability is only reasonably possible, we will disclose the potential range of the loss, if estimable. We record losses related to contingencies in cost of operations or general and administration expenses, depending on the nature of the underlying transaction leading to the loss contingency. See Note 13, Commitments and Contingencies for disclosure about loss contingencies, as applicable. Contingent liabilities accounted for under purchase accounting are recorded at their fair values. These fair values may be different from the values we would have otherwise recorded, had the contingent liability not been assumed as part of an acquisition of a business. See Note 5, Business Combinations and Note 15, Fair Value of Financial Instruments for disclosure about contingent consideration accounted for under purchase accounting, as applicable.

Revenue Recognition

We disaggregate our revenues by applicable service line: collection, landfill, transfer, transportation, landfill gas-to-energy, processing, and non-processing, which we refer to as our National Accounts business. Under the revenue recognition guidance, revenues are measured based on the consideration specified in a contract with a customer. The circumstances that impact the timing and amount of revenue recognized for each applicable service line may vary based on the nature of the service performed. We generally recognize revenues for services over time as we satisfy the performance obligation by transferring control over the service to the customer as the service is performed and the benefit is received and consumed by the customer. Services are typically delivered in a series as a single bundled performance obligation over either a designated period of time or for specified number of services. Services may also be delivered as a single bundled service, on a period-to-period basis, or in a spot transaction. Consideration may be variable on a per ton basis and/or fixed. Fixed consideration is allocated to each distinct service and variable consideration is allocated to the increment of time that the service is performed, and we have the contractual right to the fee. Fees are typically billed weekly, monthly, quarterly or in advance. Generally, the amount of consideration that we have the right to receive that is invoiced to the customer directly corresponds to the value of our performance completed to date. We do not disclose the amount of variable consideration included in the transaction price that is allocated to outstanding performance obligations when the variable consideration is allocated entirely to unsatisfied performance obligations or to a wholly unsatisfied promise to transfer a distinct good or service that forms part of a single performance obligation. Revenues that are not satisfied over time are recognized at a point-in-time. This typically includes the sale of recycled or organic materials, as well as renewable energy credits ("RECs"). Revenues from the sale of organic or recycled materials are recognized at a point-in-time as control of the materials transfers to the customer upon shipment or pick-up by the customer. Revenues from the sale of RECs are recognized at a point-in-time as the trade is executed and control transfers to the customer.

Payments to customers that are not in exchange for a distinct good or service are recorded as a reduction of revenues. We make rebates to certain customers associated with payments for recycled or organic materials that are received and subsequently processed and sold to other third-parties. Rebates are generally recorded as a reduction of revenues upon the sale of such materials, or upon receipt of the recycled materials at our facilities. We did not record revenues in fiscal years 2023, 2022, or 2021 from performance obligations satisfied in previous periods.

Contract receivables, which are included in Accounts receivable, net, are recorded when billed or when related revenue is earned, if earlier, and represent claims against third-parties that will be settled in cash. Accounts receivable, net includes receivables from contracts of $158,931 and $102,234 as of December 31, 2023 and December 31, 2022, respectively. Certain customers are billed in advance and, accordingly, recognition of the related revenues for which payment has been received is deferred as a contract liability until the services are provided and control transferred to the customer. Contract liabilities of $31,472 and $3,742 as of December 31, 2023 and December 31, 2022, respectively, are presented separately on the consolidated balance sheets. Due to the short-term nature of advanced billings, substantially all of the deferred revenue recognized as a contract liability as of December 31, 2022 and December 31, 2021 was recognized as revenue during fiscal years 2023 and 2022, respectively, when the services were performed. See Note 4, Revenue Recognition for disclosure over revenues by applicable service line.

Asset Impairments

Recovery of Long-Lived Assets. We continually assess whether events or changes in circumstances have occurred that may warrant revision of the estimated useful lives of our long-lived assets (other than goodwill) or whether the remaining balances of those assets should be evaluated for possible impairment. Long-lived assets include, for example, capitalized landfill costs, property and equipment, identifiable intangible assets, and operating lease right-of-use assets. Events or changes in circumstances that may indicate that an asset may be impaired include the following:

•a significant decrease in the market price of an asset or asset group;

•a significant adverse change in the extent or manner in which an asset or asset group is being used or in its physical condition;

•a significant adverse change in legal factors or in the business climate that could affect the value of an asset or asset group, including an adverse action or assessment by a regulator;

•an accumulation of costs significantly in excess of the amount originally expected for the acquisition or construction of a long-lived asset;

•a current period operating or cash flow loss combined with a history of operating or cash flow losses or a projection or forecast that demonstrates continuing losses associated with the use of a long-lived asset or asset group;

•a current expectation that, more likely than not, a long-lived asset or asset group will be sold or otherwise disposed of significantly before the end of its previously estimated useful life; or

•an impairment of goodwill at a reporting unit.

There are certain indicators listed above that require significant judgment and understanding of the waste industry when applied to landfill development or expansion. For example, a regulator may initially deny a landfill expansion permit application although the expansion permit is ultimately granted. In addition, management may periodically divert waste from one landfill to another to conserve remaining permitted landfill airspace. Therefore, certain events could occur in the ordinary course of business and not necessarily be considered indicators of impairment due to the unique nature of the waste industry.

If an impairment indicator occurs, we perform a test of recoverability by comparing the carrying value of the asset or asset group to its undiscounted expected future cash flows. We group our long-lived assets for this purpose at the lowest level for which identifiable cash flows are primarily independent of the cash flows of other assets or asset groups. If the carrying values are in excess of undiscounted expected future cash flows, we measure any impairment by comparing the fair value of the asset or asset group to its carrying value.

To determine fair value, we use discounted cash flow analyses and estimates about the future cash flows of the asset or asset group. This analysis includes a determination of an appropriate discount rate, the amount and timing of expected future cash flows and growth rates. The cash flows employed in our discounted cash flow analyses are typically based on financial forecasts developed internally by management. The discount rate used is commensurate with the risks involved. We may also rely on third-party valuations and or information available regarding the market value for similar assets.

If the fair value of an asset or asset group is determined to be less than the carrying amount of the asset or asset group, impairment in the amount of the difference is recorded in the period that the impairment occurs. Estimating future cash flows requires significant judgment and projections may vary from the cash flows eventually realized.

Goodwill. We annually assess goodwill for impairment during the fourth quarter of our fiscal year or more frequently if events or circumstances indicate that impairment may exist.

We may assess whether a goodwill impairment exists using either a qualitative or a quantitative assessment. If we perform a qualitative assessment, it involves determining whether events or circumstances exist that indicate it is more likely than not that the fair value of a reporting unit is less than its carrying amount, including goodwill. If based on this qualitative assessment we determine it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, we will not perform a quantitative assessment. If the qualitative assessment indicates that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, or if we elect not to perform a qualitative assessment, we perform a quantitative assessment to determine whether goodwill impairment exists at the reporting unit.

In testing for goodwill impairment, we estimate the fair value of each reporting unit, which we have determined to be our geographic operating segments and our Resource Solutions operating segment, and compare the fair value with the carrying value of the net assets of each reporting unit. If the fair value is less than its carrying value, then we would recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value, noting that the amount is not to exceed the total amount of goodwill allocated to that reporting unit.

To determine the fair value of each of our reporting units as a whole we use discounted cash flow analyses, which require significant assumptions and estimates about the future operations of each reporting unit. Significant judgments inherent in this analysis include the determination of appropriate discount rates, the amount and timing of expected future cash flows and growth rates. The cash flows employed in our discounted cash flow analyses are based on financial forecasts developed internally by management. Our discount rate assumptions are based on an assessment of our risk adjusted discount rate, applicable for each reporting unit. In assessing the reasonableness of our determined fair values of our reporting units, we evaluate our results against our current market capitalization.

If the fair value of goodwill is less than its carrying value for a reporting unit, an impairment charge would be recorded to earnings. The loss recognized cannot exceed the carrying amount of goodwill. After a goodwill impairment loss is recognized, the adjusted carrying amount of goodwill becomes its new accounting basis.

In addition to an annual goodwill impairment assessment, we would evaluate a reporting unit for impairment if events or circumstances change between annual tests indicating a possible impairment. Examples of such events or circumstances include the following:

•a significant adverse change in legal status or in the business climate;

•an adverse action or assessment by a regulator;

•a more likely than not expectation that an operating segment or a significant portion thereof will be sold; or

•the testing for recoverability of a significant asset group within the operating segment.

We elected to perform a quantitative analysis as part of our annual goodwill impairment test for fiscal year 2023. As of October 1, 2023, our Eastern, Western, Mid-Atlantic and Resource Solutions reporting units indicated that the fair value of each reporting unit exceeded its carrying amount, including goodwill. In the case of our Eastern, Western and Resource Solutions reporting units, the fair value of each reporting unit exceeded its carrying value by in excess of 30%. In the case of our Mid-Atlantic reporting unit, the fair value of the reporting unit exceeded its carrying value by approximately 10% due to the proximity of the acquisition date. We incurred no impairment of goodwill as a result of our annual goodwill impairment tests in fiscal years 2023, 2022 or 2021. However, there can be no assurance that goodwill will not be impaired at any time in the future.

Cost Method Investments. We monitor and assess the carrying value of our cost method investments throughout the year for potential impairment and write them down to their fair value when other-than-temporary declines exist. We incurred no impairment of cost method investments in fiscal year 2023, 2022 or 2021. There can be no assurance that our cost method investments will not be impaired at any time in the future.

Defined Benefit Pension Plan

We make contributions to one qualified multiemployer defined benefit pension plan ("Pension Plan"). The Pension Plan provides retirement benefits to participants based on their service. We do not administer this plan. The Pension Plan’s benefit formula is based on credited years of service and hours worked as defined in the Pension Plan document. Our pension contributions are made in accordance with funding standards established by the Employee Retirement Income Security Act of 1974 and the Internal Revenue Code, as amended by the Pension Protection Act of 2006. The Pension Plan’s assets have been invested as determined by the Pension Plan's fiduciaries in accordance with the Pension Plan's investment policy. The Pension Plan’s asset allocation is based on the Pension Plan's investment policy and is reviewed as deemed necessary. See Note 16, Employee Benefit Plans for disclosure about the Pension Plan.

Stock-Based Compensation

Our equity awards granted generally consist of stock options, restricted stock awards, restricted stock units and market-based performance stock units. The fair value of each stock option grant is estimated using a Black-Scholes option-pricing model. The fair value of restricted stock award and restricted stock unit grants is at a price equal to the fair market value of our Class A common stock at the date of grant. Compensation expense associated with our stock options, restricted stock awards and restricted stock units is recognized as expense in general and administration expense over the employee’s requisite service period. The fair value of market-based performance stock unit grants is valued using a Monte Carlo pricing model and compensation expense is recognized as expense in general and administration expense ratably over the performance period based on our estimated achievement of the established performance criteria. For purposes of calculating stock-based compensation expense, forfeitures are accounted for as they occur. See Note 14, Stockholders' Equity for disclosure about stock-based compensation.

Earnings per Share

Basic earnings per share is computed by dividing net income by the weighted average number of common shares outstanding during the period. Diluted earnings per share is computed by dividing net income by the combined weighted average number of common shares outstanding during the period and potentially dilutive shares. Dilutive shares include the assumed exercise of employee stock options, unvested restricted stock awards, unvested restricted stock units and unvested market-based performance stock units based on the expected achievement of performance targets. In computing diluted earnings per share, we utilize the treasury stock method. See Note 19, Earnings Per Share for disclosure about the calculation of earnings per share.

Subsequent Events

We have evaluated subsequent events or transactions that have occurred after the consolidated balance sheet date of December 31, 2023 through the date of this filing of the consolidated financial statements with the SEC on this Annual Report on Form 10-K and determined that, except as disclosed, there have been no material subsequent events that have occurred since December 31, 2023 through the date of this filing that would require recognition or disclosure in our consolidated financial statements.

BUSINESS COMBINATIONS - Narrative (Detail) - business	12 Months Ended
BUSINESS COMBINATIONS - Narrative (Detail) - business	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Number of businesses acquired	7	14	10
Intangible assets, useful life	10 years
Minimum
Business Acquisition [Line Items]
Intangible assets, useful life	2 years
Maximum
Business Acquisition [Line Items]
Intangible assets, useful life	10 years
Solid-Waste Collection Businesses
Business Acquisition [Line Items]
Number of businesses acquired	5

Cover Page - USD ($) $ in Billions	12 Months Ended
Cover Page - USD ($) $ in Billions	Dec. 31, 2023	Jan. 31, 2024	Jun. 30, 2023
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	000-23211
Entity Registrant Name	CASELLA WASTE SYSTEMS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	03-0338873
Entity Address, Address Line One	25 Greens Hill Lane
Entity Address, City or Town	Rutland
Entity Address, State or Province	VT
Entity Address, Postal Zip Code	05701
City Area Code	(802
Local Phone Number	775-0325
Title of 12(b) Security	Class A common stock, $0.01 par value per share
Trading Symbol	CWST
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 5.1
Documents Incorporated by Reference	Part III of this Annual Report on Form 10-K incorporates by reference information from the definitive Proxy Statement for the registrant’s 2024 Annual Meeting of Stockholders or a Form10-K/A to be filed with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year ended December 31, 2023
Entity Central Index Key	0000911177
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		57,007,273
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		988,200

STOCKHOLDERS' EQUITY - Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 497,900	$ 422,457	$ 362,142
Income tax provision (benefit) related to items in other comprehensive income (loss)	4,582	(4,095)	(2,086)
Other comprehensive (loss) income, net of tax	(8,622)	12,645	6,414
Ending balance	1,021,791	497,900	422,457
Accumulated income (loss), net, cash flow hedge
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	7,542	(5,103)	(11,517)
Other comprehensive income (loss) before reclassifications	(6,843)	15,297	3,737
Amounts reclassified from accumulated other comprehensive income (loss)	(6,361)	1,443	4,763
Income tax provision (benefit) related to items in other comprehensive income (loss)	4,582	(4,095)	(2,086)
Other comprehensive (loss) income, net of tax	(8,622)	12,645	6,414
Ending balance	$ (1,080)	$ 7,542	$ (5,103)

- Definition

Amount of equity (deficit) attributable to parent. Excludes temporary equity and equity attributable to noncontrolling interest.

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+ Details

OTHER ACCRUED LIABILITIES (Tables)

12 Months Ended

Dec. 31, 2023

Payables and Accruals [Abstract]

Schedule of Accrued Liabilities

Other accrued liabilities, classified as current liabilities, at December 31, 2023 and 2022 are as follows:


	December 31,
	2023		2022
Accrued capital expenditures	$	7,362	$	10,842
Other accrued liabilities	41,094		35,395
Total	$	48,456	$	46,237

REVENUE RECOGNITION (Details) - USD ($) $ in Thousands	12 Months Ended
REVENUE RECOGNITION (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,264,542	$ 1,085,089	$ 889,211
Eastern
Disaggregation of Revenue [Line Items]
Total revenues	374,463	340,058	264,569
Western
Disaggregation of Revenue [Line Items]
Total revenues	511,640	445,153	389,520
Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	85,640	0	0
Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	292,799	299,878	235,122
Collection
Disaggregation of Revenue [Line Items]
Total revenues	710,590	539,587	442,685
Collection \| Eastern
Disaggregation of Revenue [Line Items]
Total revenues	266,991	233,043	175,816
Collection \| Western
Disaggregation of Revenue [Line Items]
Total revenues	358,883	306,544	266,869
Collection \| Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	84,716	0	0
Collection \| Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Landfill
Disaggregation of Revenue [Line Items]
Total revenues	101,001	97,542	91,973
Landfill \| Eastern
Disaggregation of Revenue [Line Items]
Total revenues	28,275	27,301	25,241
Landfill \| Western
Disaggregation of Revenue [Line Items]
Total revenues	72,726	70,241	66,732
Landfill \| Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Landfill \| Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Transfer
Disaggregation of Revenue [Line Items]
Total revenues	122,955	110,562	91,282
Transfer \| Eastern
Disaggregation of Revenue [Line Items]
Total revenues	65,401	65,800	53,882
Transfer \| Western
Disaggregation of Revenue [Line Items]
Total revenues	56,630	44,762	37,400
Transfer \| Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	924	0	0
Transfer \| Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Transportation
Disaggregation of Revenue [Line Items]
Total revenues	20,626	19,867	13,730
Transportation \| Eastern
Disaggregation of Revenue [Line Items]
Total revenues	4,994	5,619	1,683
Transportation \| Western
Disaggregation of Revenue [Line Items]
Total revenues	15,632	14,248	12,047
Transportation \| Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Transportation \| Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	6,617	7,519	5,138
Landfill gas-to-energy \| Eastern
Disaggregation of Revenue [Line Items]
Total revenues	806	925	1,052
Landfill gas-to-energy \| Western
Disaggregation of Revenue [Line Items]
Total revenues	5,811	6,594	4,086
Landfill gas-to-energy \| Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Landfill gas-to-energy \| Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Processing
Disaggregation of Revenue [Line Items]
Total revenues	115,951	129,179	102,604
Processing \| Eastern
Disaggregation of Revenue [Line Items]
Total revenues	7,996	7,370	6,895
Processing \| Western
Disaggregation of Revenue [Line Items]
Total revenues	1,958	2,764	2,386
Processing \| Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Processing \| Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	105,997	119,045	93,323
National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	186,802	180,833	141,799
National Accounts \| Eastern
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
National Accounts \| Western
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
National Accounts \| Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
National Accounts \| Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	186,802	180,833	141,799
Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	37,848	55,335	65,551
Transferred at a point-in-time \| Eastern
Disaggregation of Revenue [Line Items]
Total revenues	463	462	166
Transferred at a point-in-time \| Western
Disaggregation of Revenue [Line Items]
Total revenues	2,731	2,138	1,719
Transferred at a point-in-time \| Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Transferred at a point-in-time \| Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	34,654	52,735	63,666
Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	1,226,694	1,029,754	823,660
Transferred over time \| Eastern
Disaggregation of Revenue [Line Items]
Total revenues	374,000	339,596	264,403
Transferred over time \| Western
Disaggregation of Revenue [Line Items]
Total revenues	508,909	443,015	387,801
Transferred over time \| Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	85,640	0	0
Transferred over time \| Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	$ 258,145	$ 247,143	$ 171,456

COMMITMENTS AND CONTINGENCIES - Schedule of Future Minimum Rental (Detail) $ in Thousands	Dec. 31, 2023 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Fiscal year ending December 31, 2024	$ 1,499
Fiscal year ending December 31, 2025	308
Fiscal year ending December 31, 2026	318
Fiscal year ending December 31, 2027	299
Fiscal year ending December 31, 2028	306
Thereafter	3,704
Total	$ 6,434

LEASES - Schedule of Lease Costs and Other Lease Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Lease cost:
Amortization of right-of-use assets	$ 7,383	$ 6,339
Interest expense	1,840	1,638
Fixed lease cost	15,318	13,804
Short-term lease cost	5,313	3,884
Variable lease cost	604	522
Total lease cost	30,458	26,187
Cash paid for amounts included in the measurement of lease liabilities:
Financing cash flows for finance leases	8,981	7,847
Operating cash flows for operating leases	10,578	10,009
Right-of-use assets obtained in exchange for new finance lease liabilities	12,211	11,919
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 19,796	9,835
Weighted-average remaining lease term - finance leases (years)	4 years 10 months 24 days
Weighted-average remaining lease term - operating leases (years)	9 years 10 months 24 days
Weighted-average discount rate - finance leases	4.00%
Weighted-average discount rate - operating leases	4.70%
Machinery and equipment
Lease cost:
Fixed lease cost	$ 6,292	5,130
Landfills
Lease cost:
Fixed lease cost	$ 9,026	$ 8,674

FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS (Tables)

12 Months Ended

Dec. 31, 2023

Asset Retirement Obligation Disclosure [Abstract]

Schedule of Changes to Accrued Capping, Closure and Post-Closure Liabilities

The changes to accrued final capping, closure and post-closure liabilities are as follows:


	Fiscal Year Ended December 31,
	2023		2022
Beginning balance	$	113,678	$	86,914
Obligations incurred	5,447		4,857
Revisions in estimates (1)	14,030		18,415
Accretion expense	9,529		7,565
Obligations settled (2)	(11,801)		(4,073)
Write-off of capping payments (3)	3,021		—
Ending balance	$	133,904	$	113,678

(1)Relates to changes in estimates and assumptions concerning anticipated waste flow, costs, including as a result of higher inflation, and timing of future final capping, closure and post-closure activities at our landfills.

(2)May include amounts paid and amounts that are being processed through accounts payable as a part of our disbursement cycle.

(3)Relates to the write-off of $3,021 of historical payments associated with capping work that has been deemed no longer viable due to a veneer failure at the Ontario County Landfill that we operate. See Note 18, Other Items and Charges for additional disclosure.

SEGMENT REPORTING - Summary of Revenue Attributable to Services Provided by Company (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue from External Customer [Line Items]
Revenues	$ 1,264,542	$ 1,085,089	$ 889,211
Product concentration risk \| Revenue
Revenue from External Customer [Line Items]
Revenues percentage	100.00%	100.00%	100.00%
Solid waste operations
Revenue from External Customer [Line Items]
Revenues	$ 971,743	$ 785,211	$ 654,089
Solid waste operations \| Product concentration risk \| Revenue
Revenue from External Customer [Line Items]
Revenues percentage	76.80%	72.40%	73.60%
Collection
Revenue from External Customer [Line Items]
Revenues	$ 710,590	$ 539,587	$ 442,685
Collection \| Product concentration risk \| Revenue
Revenue from External Customer [Line Items]
Revenues percentage	56.20%	49.70%	49.80%
Disposal
Revenue from External Customer [Line Items]
Revenues	$ 244,582	$ 227,971	$ 196,985
Disposal \| Product concentration risk \| Revenue
Revenue from External Customer [Line Items]
Revenues percentage	19.30%	21.00%	22.20%
Power generation
Revenue from External Customer [Line Items]
Revenues	$ 6,617	$ 7,519	$ 5,138
Power generation \| Product concentration risk \| Revenue
Revenue from External Customer [Line Items]
Revenues percentage	0.50%	0.70%	0.60%
Processing
Revenue from External Customer [Line Items]
Revenues	$ 9,954	$ 10,134	$ 9,281
Processing \| Product concentration risk \| Revenue
Revenue from External Customer [Line Items]
Revenues percentage	0.80%	1.00%	1.00%
Resource Solutions operations
Revenue from External Customer [Line Items]
Revenues	$ 292,799	$ 299,878	$ 235,122
Resource Solutions operations \| Product concentration risk \| Revenue
Revenue from External Customer [Line Items]
Revenues percentage	23.20%	27.60%	26.40%
Processing
Revenue from External Customer [Line Items]
Revenues	$ 105,997	$ 119,045	$ 93,323
Processing \| Product concentration risk \| Revenue
Revenue from External Customer [Line Items]
Revenues percentage	8.40%	10.90%	10.50%
National Accounts
Revenue from External Customer [Line Items]
Revenues	$ 186,802	$ 180,833	$ 141,799
National Accounts \| Product concentration risk \| Revenue
Revenue from External Customer [Line Items]
Revenues percentage	14.80%	16.70%	15.90%

GOODWILL AND INTANGIBLE ASSETS - Schedule of Activity and Balances Related to Goodwill by Reporting Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 274,458	$ 232,860
Acquisitions	461,159	40,707
Measurement Period Adjustments	53	891
Goodwill, ending balance	735,670	274,458
Eastern
Goodwill [Roll Forward]
Goodwill, beginning balance	52,406	52,072
Acquisitions	21,487	93
Measurement Period Adjustments	0	241
Goodwill, ending balance	73,893	52,406
Western
Goodwill [Roll Forward]
Goodwill, beginning balance	183,286	163,728
Acquisitions	101,717	18,908
Measurement Period Adjustments	53	650
Goodwill, ending balance	285,056	183,286
Mid-Atlantic
Goodwill [Roll Forward]
Goodwill, beginning balance	0	0
Acquisitions	332,247	0
Measurement Period Adjustments	0	0
Goodwill, ending balance	332,247	0
Resource Solutions
Goodwill [Roll Forward]
Goodwill, beginning balance	38,766	17,060
Acquisitions	5,708	21,706
Measurement Period Adjustments	0	0
Goodwill, ending balance	$ 44,474	$ 38,766

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References + Details

BUSINESS COMBINATIONS

12 Months Ended

Dec. 31, 2023

Business Combination and Asset Acquisition [Abstract]

BUSINESS COMBINATIONS

In fiscal year 2023, we acquired seven businesses: the GFL Subsidiaries, which includes solid waste collection, transfer and recycling operations in Pennsylvania, Maryland and Delaware; the assets of Consolidated Waste Services, LLC and its affiliates (dba Twin Bridges), which was completed on September 1, 2023, consisting of a collection, transfer and recycling business in the greater Albany, New York area ("Twin Bridges Acquisition"); and five additional solid waste collection businesses that provide collection, transfer and recycling services.

In fiscal year 2022, we acquired fourteen businesses primarily related to our solid waste collection, transfer, recycling and transportation operations.

In fiscal year 2021, we acquired ten businesses primarily related to our solid-waste collection, transfer and recycling operations, including a residential, commercial and roll-off collection business in eastern Connecticut that operates a rail-served construction and demolition processing and waste transfer facility, a waste transfer station, a single-stream recycling facility, and several other recycling operations.

The operating results of these businesses are included in the accompanying audited consolidated statements of operations from each date of acquisition. Due to the integration of certain of these businesses within our existing market areas, it is not practicable to segregate the revenue and earnings of all of the acquired businesses since their respective acquisitions dates.

The purchase price has been allocated to the net assets acquired based on fair values at each date of acquisition with the residual amounts recorded as goodwill. Purchase price allocations are based on information existing at the acquisition dates or upon closing the transactions, including contingent consideration. See Note 15, Fair Value of Financial Instruments for further disclosure about contingent consideration. Acquired intangible assets other than goodwill that are subject to amortization may include customer relationships, trade names and covenants not-to-compete. These are amortized over a two to ten-year period from the date of acquisition.

Goodwill acquired is primarily associated with the value of projected discounted cash flows, based on the current and anticipated operating performance of the business, in excess of the specific values allocated to other assets, new growth opportunities from the expansion of our geographic operating footprint into the Mid-Atlantic market in fiscal year 2023, and expected synergies from combining the acquired businesses with our existing operations and implementing our operating strategies. Substantially all amounts recorded to goodwill are expected to be deductible for tax purposes.

A summary of the purchase price paid and the purchase price allocation for acquisitions follows:


	Fiscal Year Ended December 31,
	2023		2022		2021
Purchase Price:
Cash used in acquisitions, net of cash acquired	$	846,711	$	76,573	$	166,489


Other non-cash consideration	—		1,275		—
Open working capital settlements due from sellers	(2,873)		—		—
Holdbacks, additional consideration owed to sellers and contingent consideration	2,729		4,840		5,194
Total consideration	846,567		82,688		171,683
Allocated as follows:
Current assets (1)	19,524		7,644		7,218




Property and equipment:
Land	8,440		3,141		1,321
Finance lease right-of-use-assets	—		—		31,467
Buildings and improvements	28,411		8,576		11,046
Machinery, equipment and other	177,916		11,689		46,396
Operating lease right-of-use assets	11,786		405		6,500
Intangible assets:
Trade names	4,320		55		8,350
Covenants not-to-compete	30,860		2,424		1,807
Customer relationships	145,393		12,224		36,195
Other non-current assets	—		40		—
Deferred tax liability	(9,058)		—		—
Current liabilities	(21,417)		(3,812)		(6,014)





Other long-term liabilities	(828)		(123)		—
Financing lease liabilities, less current portion	—		—		(10,535)
Operating lease liabilities, less current portion	(9,939)		(282)		—

Fair value of assets acquired and liabilities assumed	385,408		41,981		133,751
Excess purchase price to be allocated to goodwill	$	461,159	$	40,707	$	37,932

(1)Includes contract receivables in fiscal year 2023, 2022 and 2021 of $17,002, $6,806 and $5,340, respectively.

As of December 31, 2023, certain purchase price allocations reflected in the table above, including the GFL Acquisition and the Twin Bridges Acquisition, are subject to revision upon finalization of third-party valuations over each respective one-year- measurement period. Amounts have been updated from the preliminary purchase price allocations, including the value of certain tangible and intangible assets acquired, as information has been obtained about the facts and circumstances that existed at the valuation date and remain subject to revision based on the final valuations.

Unaudited pro forma combined information that shows our operational results as though each acquisition completed since the beginning of the prior fiscal year had occurred as of January 1, 2021 is as follows.


	Fiscal Year Ended December 31,
	2023		2022		2021
Revenues	$	1,436,871	$	1,412,377	$	1,303,556
Operating income	$	89,236	$	113,842	$	99,286
Net income	$	28,507	$	60,121	$	36,200

Basic earnings per share attributable to common stockholders:
Basic weighted average shares outstanding	55,174		51,623		51,312
Basic earnings per common share	$	0.52	$	1.16	$	0.71
Diluted earnings per share attributable to common stockholders:
Diluted weighted average shares outstanding	55,274		51,767		51,515
Diluted earnings per common share	$	0.52	$	1.16	$	0.70

The unaudited pro forma results set forth in the table above have been prepared for comparative purposes only and are not necessarily indicative of the actual results of operations had the acquisitions taken place as of January 1, 2021 or the results of our future operations. Furthermore, the unaudited pro forma results do not give effect to all cost savings or incremental costs that may occur as a result of the integration and consolidation of the completed acquisitions.

DEBT - Credit Facility (Details) - USD ($)	1 Months Ended	12 Months Ended
DEBT - Credit Facility (Details) - USD ($)	Jun. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	May 31, 2023	Apr. 30, 2023
Line of Credit Facility [Line Items]
Proceeds from debt borrowings		$ 465,000,000	$ 88,200,000	$ 3,701,000
Credit Facility
Line of Credit Facility [Line Items]
Additional revolver capacity		$ 125,000,000
Commitment fee adjustment		100.00%
Floor interest rate		0.00%
Interest rate, annual increase upon payment default		2.00%
Interest rate, annual increase upon other event of default		2.00%
Credit Facility \| Minimum
Line of Credit Facility [Line Items]
Commitment fee, margin percent		0.20%
Credit Facility \| Maximum
Line of Credit Facility [Line Items]
Commitment fee, margin percent		0.40%
Credit Facility \| SOFR
Line of Credit Facility [Line Items]
Variable rate adjustment		0.10%
Credit Facility \| Base Rate
Line of Credit Facility [Line Items]
Variable rate adjustment		0.04%
Secured Debt
Line of Credit Facility [Line Items]
Bridge loan						$ 375,000,000
Secured Debt \| Credit Facility
Line of Credit Facility [Line Items]
Aggregate principal amount issued		$ 350,000,000
Secured Debt \| Term Loan A Facility ("2023 Term Loan Facility") due December 2026; bearing interest at 7.581% as of December 31, 2023
Line of Credit Facility [Line Items]
Aggregate principal amount issued		430,000,000			$ 430,000,000
Proceeds from debt borrowings	$ 430,000,000
Unsecured Debt
Line of Credit Facility [Line Items]
Bridge loan	$ 200,000,000
Line of Credit \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit drawn		$ 0
Line of Credit \| Credit Facility
Line of Credit Facility [Line Items]
Facility term		5 years
Line of Credit \| Credit Facility \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Credit facility maximum		$ 300,000,000
Remaining capacity		272,267,000
Line of Credit \| Credit Facility \| Letter of Credit
Line of Credit Facility [Line Items]
Letters of credit sublimit		$ 75,000,000
Fronting fee		0.25%
Outstanding irrevocable letters of credit totaling		$ 27,733,000

LEASES

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

LEASES

A schedule of lease costs and other lease information follows:


	Fiscal Year Ended December 31,
	2023		2022
Lease cost:
Amortization of right-of-use assets	$	7,383	$	6,339
Interest expense	1,840		1,638
Fixed lease cost - vehicles, equipment and property	6,292		5,130
Fixed lease cost - landfill operating leases	9,026		8,674
Fixed lease cost	15,318		13,804
Short-term lease cost	5,313		3,884
Variable lease cost	604		522
Total lease cost	$	30,458	$	26,187

Other information:
Cash paid for amounts included in the measurement of lease liabilities:
Financing cash flows for finance leases	$	8,981	$	7,847
Operating cash flows for operating leases	$	10,578	$	10,009
Right-of-use assets obtained in exchange for new finance lease liabilities	$	12,211	$	11,919
Right-of-use assets obtained in exchange for new operating lease liabilities	$	19,796	$	9,835

			December 31, 2023
Weighted-average remaining lease term - finance leases (years)			4.9
Weighted-average remaining lease term - operating leases (years)			9.9
Weighted-average discount rate - finance leases			4.0		%
Weighted-average discount rate - operating leases			4.7		%

Estimated minimum future lease obligations as of December 31, 2023 for each of the next five fiscal years and thereafter are as follows:


	Operating Leases		Finance Leases
Fiscal year ending December 31, 2024	$	12,293	$	12,432
Fiscal year ending December 31, 2025	12,586		12,230
Fiscal year ending December 31, 2026	11,098		11,628
Fiscal year ending December 31, 2027	12,423		7,648
Fiscal year ending December 31, 2028	7,790		6,985
Thereafter	39,230		8,900
Total lease payments	95,420		59,823
Less: interest	(20,307)		(6,757)
Lease liability balance	$	75,113	$	53,066

LEASES

A schedule of lease costs and other lease information follows:


	Fiscal Year Ended December 31,
	2023		2022
Lease cost:
Amortization of right-of-use assets	$	7,383	$	6,339
Interest expense	1,840		1,638
Fixed lease cost - vehicles, equipment and property	6,292		5,130
Fixed lease cost - landfill operating leases	9,026		8,674
Fixed lease cost	15,318		13,804
Short-term lease cost	5,313		3,884
Variable lease cost	604		522
Total lease cost	$	30,458	$	26,187

Other information:
Cash paid for amounts included in the measurement of lease liabilities:
Financing cash flows for finance leases	$	8,981	$	7,847
Operating cash flows for operating leases	$	10,578	$	10,009
Right-of-use assets obtained in exchange for new finance lease liabilities	$	12,211	$	11,919
Right-of-use assets obtained in exchange for new operating lease liabilities	$	19,796	$	9,835

			December 31, 2023
Weighted-average remaining lease term - finance leases (years)			4.9
Weighted-average remaining lease term - operating leases (years)			9.9
Weighted-average discount rate - finance leases			4.0		%
Weighted-average discount rate - operating leases			4.7		%

Estimated minimum future lease obligations as of December 31, 2023 for each of the next five fiscal years and thereafter are as follows:


	Operating Leases		Finance Leases
Fiscal year ending December 31, 2024	$	12,293	$	12,432
Fiscal year ending December 31, 2025	12,586		12,230
Fiscal year ending December 31, 2026	11,098		11,628
Fiscal year ending December 31, 2027	12,423		7,648
Fiscal year ending December 31, 2028	7,790		6,985
Thereafter	39,230		8,900
Total lease payments	95,420		59,823
Less: interest	(20,307)		(6,757)
Lease liability balance	$	75,113	$	53,066

ACCOUNTING CHANGES

12 Months Ended

Dec. 31, 2023

Accounting Changes and Error Corrections [Abstract]

ACCOUNTING CHANGES

The following table provides a brief description of a recent Accounting Standards Update ("ASU") to the Accounting Standards Codification ("ASC") issued by the Financial Accounting Standards Board (“FASB”) that we adopted and is deemed to have a possible material impact on our consolidated financial statements based on current account balances and activity:

Standard

Description

Effect on the Financial Statements or Other
Significant Matters

ASU No. 2020-04: Reference Rate Reform (Topic 848), as amended through December 2022

Provides temporary optional guidance to ease the potential burden in applying GAAP to contract modifications and hedging relationships that reference London Inter-Bank Offered Rate ("LIBOR") or another reference rate expected to be discontinued, subject to meeting certain criteria.

This guidance provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. Effective the quarter ended March 31, 2023, we elected optional expedients under this guidance that allowed us to maintain hedge effectiveness upon modifying contract terms related to reference rate reform in our amended and restated credit agreement, dated as of December 22, 2021, as amended by the first amendment, dated as of February 9, 2023, the second amendment, dated as of February 9, 2023, and the third amendment, dated as of April 25, 2023, collectively with the specified acquisition loan joinder, dated May 25, 2023 ("Loan Joinder") (the "Amended and Restated Credit Agreement") until we transitioned our interest rate derivative agreements from LIBOR to term secured overnight financing rate ("Term SOFR") in the quarter ended June 30, 2023. See Note 12, Debt. This guidance will be in effect through December 31, 2024.

The following table provides a brief description of recent ASUs to the ASC issued by the FASB that are pending adoption and deemed to have a possible material impact on our consolidated financial statements based on current account balances and activity:

Standard

Description

Effect on the Financial Statements or Other
Significant Matters

Accounting standards issued pending adoption as of December 31, 2023

ASU No. 2023-07: Improvements to Reportable Segment Disclosures (Topic 280)

Requires entities to provide additional disclosure related to the chief operating decision maker ("CODM") and reportable operating segments, including providing more detailed information about reportable operating segment's significant expenses and how that information is used by the CODM.

We are currently assessing the provisions of this guidance and expect that its adoption will have an impact on reportable operating segment disclosures within our consolidated financial statements and accompanying notes. This guidance is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted.

ASU No. 2023-09: Improvements to Income Tax Disclosures (Topic 740)

Requires entities to provide additional disclosure related to the transparency and decision usefulness of income tax disclosures, including additional disclosure around the rate reconciliation and income taxes paid,

We are currently assessing the provisions of this guidance and expect that its adoption will have an impact on income tax disclosures within our consolidated financial statements and accompanying notes. This guidance is effective for fiscal years beginning after December 15, 2024, with early adoption permitted.

- Definition

The entire disclosure for change in accounting principle. Includes, but is not limited to, nature, reason, and method of adopting amendment to accounting standards or other change in accounting principle.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
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-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (g)(2)(i)
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-URI https://asc.fasb.org//1943274/2147480016/944-40-65-2

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-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (e)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482833/825-10-65-6

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (e)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482833/825-10-65-6

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 6
-Subparagraph (e)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482833/825-10-65-6

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 4
-Subparagraph (e)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479654/326-10-65-4

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 4
-Subparagraph (e)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479654/326-10-65-4

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 926
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (f)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483194/926-20-65-2

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 926
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (f)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483194/926-20-65-2

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 926
-SubTopic 20
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (f)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483194/926-20-65-2

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480530/250-10-S99-6

Reference 29: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-1

Reference 30: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-1

Reference 31: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 250
-Publisher FASB
-URI https://asc.fasb.org//250/tableOfContent

Reference 32: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (e)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 33: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (d)(1)
-SubTopic 20
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481925/310-20-65-2

Reference 34: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (d)(2)
-SubTopic 20
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481925/310-20-65-2

+ Details

FAIR VALUE OF FINANCIAL INSTRUMENTS

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

FAIR VALUE OF FINANCIAL INSTRUMENTS

We use a three-tier fair value hierarchy to classify and disclose all assets and liabilities measured at fair value on a recurring basis, as well as assets and liabilities measured at fair value on a non-recurring basis, in periods subsequent to their initial measurement. These tiers include: Level 1, defined as quoted market prices in active markets for identical assets or liabilities; Level 2, defined as inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; and Level 3, defined as unobservable inputs that are not corroborated by market data.

We use valuation techniques that maximize the use of market prices and observable inputs and minimize the use of unobservable inputs. In measuring the fair value of our financial assets and liabilities, we rely on market data or assumptions that we believe market participants would use in pricing an asset or a liability.

Assets and Liabilities Accounted for at Fair Value on a Recurring Basis

Our financial instruments include cash and cash equivalents, accounts receivable, restricted investment securities held in trust on deposit with various banks as collateral for our obligations relative to our landfill final capping, closure and post-closure costs, interest rate derivatives, contingent consideration related to acquisitions, trade payables and debt. The carrying values of cash and cash equivalents, accounts receivable and trade payables approximate their respective fair values due to their short-term nature. The fair value of restricted investment securities held in trust, which are valued using quoted market prices, are included as restricted assets in the Level 1 tier below. The fair value of interest rate derivatives included in the Level 2 tier below is calculated using discounted cash flow valuation methodologies based upon Term SOFR yield curves that are observable at commonly quoted intervals for the full term of the swaps. The fair value of contingent consideration - acquisition included in the Level 3 tier is calculated using a discounted cash flow valuation methodology based upon a probability-weighted analysis of a success payment related to the potential attainment of a transfer station permit expansion. We recognize all derivatives accounted for on the balance sheet at fair value. See Note 12, Debt for disclosure about the fair value of debt.

Recurring Fair Value Measurements

Summaries of our financial assets and liabilities that are measured at fair value on a recurring basis are as follows:


	Fair Value Measurement at December 31, 2023 Using:
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:

Interest rate swaps	$	—	$	10,364	$	—
Restricted investment securities - landfill closure	2,203		—		—
	$	2,203	$	10,364	$	—
Liabilities:
Interest rate swaps	$	—	$	11,762	$	—
	$	—	$	11,762	$	—


	Fair Value Measurement at December 31, 2022 Using:
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Interest rate swaps	$	—	$	11,806	$	—

Restricted investment securities - landfill closure	1,900		—		—
	$	1,900	$	11,806	$	—
Liabilities:
Interest rate swaps	$	—	$	—	$	—
Contingent consideration - acquisition (1)	—		—		965
	$	—	$	—	$	965

(1)In the fiscal year ended December 31, 2023, we recorded a gain on resolution of acquisition-related contingent consideration of $965, within cost of operations, associated with the reversal of a contingency for a transfer station permit expansion that is no longer deemed viable.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

STOCKHOLDERS' EQUITY - Narrative (Detail) $ / shares in Units, $ in Thousands			12 Months Ended
	Jun. 16, 2023 USD ($) $ / shares shares	Jun. 01, 2023 shares	Dec. 31, 2023 USD ($) vote $ / shares shares	Dec. 31, 2022 USD ($) vote shares	Dec. 31, 2021 USD ($)
Limited Partners' Capital Account [Line Items]
Preferred stock authorized to issue (up to) (in shares) \| shares			944,000
Shares issued \| shares			0	0
Expected dividend yield			0.00%
Expected volatility			30.00%
Total fair value of other stock awards vested			$ 12,048	$ 17,011	$ 20,106
Income benefit associated with stock-based compensation expense			(2,330)	(1,744)	(2,304)
Restricted Stock Awards
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense			8
Stock Options
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense			516	248	28
Aggregate intrinsic value of stock options exercised			1,302	1,467	1,238
Unrecognized stock-based compensation expense, options			$ 2,108
Unrecognized stock-based compensation expense, weighted average period			3 years 10 months 24 days
Expected life			5 years 7 months 6 days
Risk-free interest rate			4.60%
Restricted Stock, Restricted Stock Units and Performance Stock Units
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense			$ 8,116	7,530	11,241
Restricted Stock Units
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense			$ 5,362
Market-based Performance Stock Units
Limited Partners' Capital Account [Line Items]
Expected dividend yield			0.00%
Risk-free interest rate			4.30%
Expected volatility			34.90%
Weighted average fair value of market-based performance (in dollars per share) \| $ / shares			$ 83.16
Amended and Restated 1997 Employee Stock Purchase Plan
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense			$ 451	$ 376	$ 281
Non-Employee Director \| Restricted Stock Awards
Limited Partners' Capital Account [Line Items]
Options vesting period			3 years
Maximum \| Performance Stock Units
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense			$ 4,377
Weighted Average \| Restricted Stock Awards
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense, weighted average period			6 months
Weighted Average \| Restricted Stock Units
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense, weighted average period			2 years 3 months 18 days
Weighted Average \| Performance Stock Units
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense, weighted average period			1 year 7 months 6 days
2016 Incentive Plan
Limited Partners' Capital Account [Line Items]
Options granted period			10 years
2016 Incentive Plan \| Minimum
Limited Partners' Capital Account [Line Items]
Options vesting period			1 year
2016 Incentive Plan \| Maximum
Limited Partners' Capital Account [Line Items]
Options vesting period			5 years
Class A Common Stock
Limited Partners' Capital Account [Line Items]
Sale of stock, number of shares issued \| shares	6,053,000		6,053
Sale of stock, price per share (in dollars per share) \| $ / shares	$ 85.50
Sale of stock, net proceeds	$ 496,231
Vote for each share held (in votes per share) \| vote			1
Common stock, additional authorized shares \| shares		400,000
Number of shares available for future grant \| shares			407,000
Class A Common Stock \| 2016 Incentive Plan
Limited Partners' Capital Account [Line Items]
Common stock, authorized shares \| shares			2,250,000
Common stock, additional authorized shares \| shares			2,723,000
Number of shares available for future grant \| shares			616,000
Class B Common Stock
Limited Partners' Capital Account [Line Items]
Vote for each share held (in votes per share) \| vote			10	10

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Self-Insurance Liabilities and Related Costs (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Capital Leased Assets [Line Items]
Maximum exposure per individual event	$ 1,250
Self insurance reserves	22,427	$ 22,184
Automobile Plan \| Minimum
Capital Leased Assets [Line Items]
Potential exposure per individual event	1,750
Automobile Plan \| Maximum
Capital Leased Assets [Line Items]
Potential exposure per individual event	$ 3,875

LEASES (Tables)

12 Months Ended

Dec. 31, 2023

Leases [Abstract]

Schedule of Lease Costs and Other Lease Information

A schedule of lease costs and other lease information follows:


	Fiscal Year Ended December 31,
	2023		2022
Lease cost:
Amortization of right-of-use assets	$	7,383	$	6,339
Interest expense	1,840		1,638
Fixed lease cost - vehicles, equipment and property	6,292		5,130
Fixed lease cost - landfill operating leases	9,026		8,674
Fixed lease cost	15,318		13,804
Short-term lease cost	5,313		3,884
Variable lease cost	604		522
Total lease cost	$	30,458	$	26,187

Other information:
Cash paid for amounts included in the measurement of lease liabilities:
Financing cash flows for finance leases	$	8,981	$	7,847
Operating cash flows for operating leases	$	10,578	$	10,009
Right-of-use assets obtained in exchange for new finance lease liabilities	$	12,211	$	11,919
Right-of-use assets obtained in exchange for new operating lease liabilities	$	19,796	$	9,835

			December 31, 2023
Weighted-average remaining lease term - finance leases (years)			4.9
Weighted-average remaining lease term - operating leases (years)			9.9
Weighted-average discount rate - finance leases			4.0		%
Weighted-average discount rate - operating leases			4.7		%

Schedule of Estimated Minimum Future Finance Lease Obligations

Estimated minimum future lease obligations as of December 31, 2023 for each of the next five fiscal years and thereafter are as follows:


	Operating Leases		Finance Leases
Fiscal year ending December 31, 2024	$	12,293	$	12,432
Fiscal year ending December 31, 2025	12,586		12,230
Fiscal year ending December 31, 2026	11,098		11,628
Fiscal year ending December 31, 2027	12,423		7,648
Fiscal year ending December 31, 2028	7,790		6,985
Thereafter	39,230		8,900
Total lease payments	95,420		59,823
Less: interest	(20,307)		(6,757)
Lease liability balance	$	75,113	$	53,066

Schedule of Estimated Minimum Future Operating Lease Obligations

Estimated minimum future lease obligations as of December 31, 2023 for each of the next five fiscal years and thereafter are as follows:


	Operating Leases		Finance Leases
Fiscal year ending December 31, 2024	$	12,293	$	12,432
Fiscal year ending December 31, 2025	12,586		12,230
Fiscal year ending December 31, 2026	11,098		11,628
Fiscal year ending December 31, 2027	12,423		7,648
Fiscal year ending December 31, 2028	7,790		6,985
Thereafter	39,230		8,900
Total lease payments	95,420		59,823
Less: interest	(20,307)		(6,757)
Lease liability balance	$	75,113	$	53,066

PROPERTY AND EQUIPMENT - Components of Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Finance lease right-of-use assets	$ 101,770	$ 90,362
Total property and equipment	2,148,094	1,785,306
Less: accumulated depreciation and amortization	(1,167,541)	(1,064,756)
Property, plant and equipment and finance lease right-of-use assets, net	980,553	720,550
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	47,863	37,321
Landfills
Property, Plant and Equipment [Line Items]
Property and equipment, gross	786,130	730,914
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	262,204	209,234
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	287,175	243,359
Rolling stock
Property, Plant and Equipment [Line Items]
Property and equipment, gross	396,247	276,282
Containers
Property, Plant and Equipment [Line Items]
Property and equipment, gross	266,705	197,834
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 74,408	$ 53,439

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Revenues	$ 1,264,542	$ 1,085,089	$ 889,211
Operating expenses:
Cost of operations	832,038	723,117	582,403
General and administration	155,847	133,419	118,834
Depreciation and amortization	170,705	126,351	103,590
Expense from acquisition activities	15,038	4,613	5,304
Legal settlement	6,150	0	0
Landfill capping charge - veneer failure	3,870	0	0
Southbridge Landfill closure charge, net	467	1,436	496
Environmental remediation charge	0	759	924
Total operating expenses	1,184,115	989,695	811,551
Operating income	80,427	95,394	77,660
Other expense (income):
Interest income	(10,741)	(709)	(302)
Interest expense	47,578	23,722	21,229
Loss from termination of bridge financing	8,191	0	0
Other income	(1,646)	(2,585)	(1,313)
Other expense, net	43,382	20,428	19,614
Income before income taxes	37,045	74,966	58,046
Provision for income taxes	11,646	21,887	16,946
Net income	$ 25,399	$ 53,079	$ 41,100
Basic earnings per share attributable to common stockholders:
Weighted average common shares outstanding	55,174	51,623	51,312
Basic earnings per common share (in dollars per share)	$ 0.46	$ 1.03	$ 0.80
Diluted earnings per share attributable to common stockholders:
Weighted average common shares outstanding	55,274	51,767	51,515
Diluted earnings per common share (in dollars per share)	$ 0.46	$ 1.03	$ 0.80

INCOME TAXES - Narrative (Detail) - USD ($)	12 Months Ended
INCOME TAXES - Narrative (Detail) - USD ($)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Change in valuation allowance, benefit	$ (912,000)	$ 1,425,000	$ 388,000	$ 61,317,000
Valuation allowance	5,580,000	4,668,000
Increase (decrease) in valuation allowance	912,000
Net deferred tax asset	10,597,000	22,466,000
Net operating loss carryforwards subject to expiration	7,152,000
Net operating loss carryforwards not subject to expiration	125,665,000
State net operating loss carryforwards, state and local	28,262,000
General business credit carryforward	6,722,000
Unrecognized tax benefits	0	$ 0
Federal
Operating Loss Carryforwards [Line Items]
Net deferred tax asset	11,224,000
State
Operating Loss Carryforwards [Line Items]
Net deferred tax liability	(627,000)
Tax credit carryforwards	176,000
Complete Disposal Company, Inc
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 1,756,000

SEGMENT REPORTING - Summary of Financial Information by Reportable Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Revenues	$ 1,264,542	$ 1,085,089	$ 889,211
Depreciation and amortization	170,705	126,351	103,590
Operating income (loss)	80,427	95,394	77,660
Interest expense, net	36,837	23,013	20,927
Capital expenditures	154,907	130,960	123,295
Goodwill	735,670	274,458	232,860
Total assets	2,535,470	1,449,215	1,283,580
Eastern
Segment Reporting Information [Line Items]
Goodwill	73,893	52,406	52,072
Western
Segment Reporting Information [Line Items]
Goodwill	285,056	183,286	163,728
Mid-Atlantic
Segment Reporting Information [Line Items]
Goodwill	332,247	0	0
Resource Solutions
Segment Reporting Information [Line Items]
Goodwill	44,474	38,766	17,060
Operating Segments \| Eastern
Segment Reporting Information [Line Items]
Revenues	374,463	340,058	264,569
Depreciation and amortization	50,881	47,673	33,572
Operating income (loss)	27,198	16,559	12,937
Interest expense, net	638	565	456
Capital expenditures	43,817	38,501	31,489
Goodwill	73,893	52,406	52,072
Total assets	434,323	372,895	357,446
Operating Segments \| Western
Segment Reporting Information [Line Items]
Revenues	511,640	445,153	389,520
Depreciation and amortization	82,291	64,116	61,055
Operating income (loss)	62,318	65,453	49,035
Interest expense, net	380	508	159
Capital expenditures	82,706	65,190	72,892
Goodwill	285,056	183,286	163,728
Total assets	1,001,090	737,658	688,826
Operating Segments \| Mid-Atlantic
Segment Reporting Information [Line Items]
Revenues	85,640	0	0
Depreciation and amortization	20,263	0	0
Operating income (loss)	(5,790)	0	0
Interest expense, net	0	0	0
Capital expenditures	5,271	0	0
Goodwill	332,247	0	0
Total assets	553,339	0	0
Operating Segments \| Resource Solutions
Segment Reporting Information [Line Items]
Revenues	292,799	299,878	235,122
Depreciation and amortization	14,202	12,082	7,060
Operating income (loss)	5,639	15,862	17,591
Interest expense, net	143	146	168
Capital expenditures	14,586	15,172	12,094
Goodwill	44,474	38,766	17,060
Total assets	253,090	191,118	127,304
Inter-company revenue
Segment Reporting Information [Line Items]
Revenues	(281,736)	(239,951)	(202,298)
Inter-company revenue \| Eastern
Segment Reporting Information [Line Items]
Revenues	(92,938)	(83,201)	(66,126)
Inter-company revenue \| Western
Segment Reporting Information [Line Items]
Revenues	(173,044)	(151,016)	(132,914)
Inter-company revenue \| Mid-Atlantic
Segment Reporting Information [Line Items]
Revenues	(417)	0	0
Inter-company revenue \| Resource Solutions
Segment Reporting Information [Line Items]
Revenues	(15,337)	(5,734)	(3,258)
Corporate Entities
Segment Reporting Information [Line Items]
Revenues	0	0	0
Depreciation and amortization	3,068	2,480	1,903
Operating income (loss)	(8,938)	(2,480)	(1,903)
Interest expense, net	35,676	21,794	20,144
Capital expenditures	8,527	12,097	6,820
Goodwill	0	0	0
Total assets	$ 293,628	$ 147,544	$ 110,004

ACCOUNTING CHANGES (Policies)

12 Months Ended

Dec. 31, 2023

Accounting Changes and Error Corrections [Abstract]

Basis of Accounting

Casella Waste Systems, Inc. (“Parent”) and its subsidiaries (collectively, “we”, “us” or “our”), is a regional, vertically integrated solid waste services company. We provide resource management expertise and services to residential, commercial, municipal, institutional and industrial customers, primarily in the areas of solid waste collection and disposal, transfer, recycling and organics services.

We provide integrated solid waste services in nine states: Vermont, New Hampshire, New York, Massachusetts, Connecticut, Maine, Pennsylvania, Delaware and Maryland, with our headquarters located in Rutland, Vermont. On June 30, 2023, we acquired the equity interests of four wholly owned subsidiaries of GFL Environmental Inc. ("GFL Subsidiaries"), which are the basis of our newly formed regional operating segment, the Mid-Atlantic region, that expanded our integrated solid waste services into the states of Delaware and Maryland ("GFL Acquisition"). See Note 5, Business Combinations for further disclosure. Operations under the Mid-Atlantic region commenced on July 1, 2023. The GFL Acquisition was funded from financing transactions (see Note 12, Debt for further disclosure), the net proceeds from an equity offering completed June 16, 2023 (see Note 14, Stockholders’ Equity for further disclosure) and cash on hand.

We manage our solid waste operations on a geographic basis through three regional operating segments, the Eastern, Western and Mid-Atlantic regions, each of which provides a comprehensive range of non-hazardous solid waste services. We manage our resource renewal operations through the Resource Solutions operating segment, which leverages our core competencies in materials processing, industrial recycling, organics and resource management service offerings to deliver a comprehensive solution for our larger commercial, municipal, institutional and industrial customers that have more diverse waste and recycling needs. Legal, tax, information technology, human resources, certain finance and accounting and other administrative functions are included in our Corporate Entities segment.

The accompanying consolidated financial statements, which include the accounts of the Parent and our wholly-owned subsidiaries have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). All significant intercompany accounts and transactions are eliminated in consolidation. Investments in entities in which we do not have a controlling financial interest are accounted for under either the equity method or the cost method of accounting, as appropriate.

Accounting Standards Adopted and Pending Adoption

Standard

Description

Effect on the Financial Statements or Other
Significant Matters

ASU No. 2020-04: Reference Rate Reform (Topic 848), as amended through December 2022

Standard

Description

Effect on the Financial Statements or Other
Significant Matters

Accounting standards issued pending adoption as of December 31, 2023

ASU No. 2023-07: Improvements to Reportable Segment Disclosures (Topic 280)

ASU No. 2023-09: Improvements to Income Tax Disclosures (Topic 740)

Management's Estimates and Assumptions

Management’s Estimates and Assumptions

Cash and Cash Equivalents

We consider all highly liquid investments purchased with original maturities of three months or less to be cash equivalents.

Concentrations of Credit Risk

Accounts Receivable, Net of Allowance for Credit Losses

Inventory

Inventory includes secondary fibers, recyclables ready for sale, and parts and supplies. Inventory is stated at the lower of cost (first-in, first-out) or market.

Property and Equipment


Asset Classification						Estimated Useful Life
Buildings and improvements						10-30 years
Machinery and equipment						5-10 years
Rolling stock						5-10 years
Containers						5-12 years
Furniture and Fixtures						3-8 years

The cost of maintenance and repairs is charged to operations as incurred.

Landfill Accounting

Life Cycle Accounting

Landfill Development Costs

Landfill Airspace

We apply the following guidelines in determining a landfill’s remaining permitted and expansion airspace:

•we control the land on which the expansion is sought;

•all technical siting criteria have been met or a variance has been obtained or is reasonably expected to be obtained;

•we have not identified any legal or political impediments which we believe will not be resolved in our favor;

•we are actively working on obtaining any necessary permits and we expect that all required permits will be received; and

•senior management has approved the project based on a review of the engineering design and determination that the financial return profile meets our investment criteria.

Final Capping, Closure and Post-Closure Costs

The following is a description of our landfill asset retirement activities and related accounting:

Lease Accounting

Goodwill and Intangible Assets

Investments in Unconsolidated Entities

Fair Value of Financial Instruments

Business Combinations

Environmental Remediation Liabilities

Self-Insurance Liabilities and Related Costs

Income Taxes

Derivatives and Hedging

Contingent Liabilities

Revenue Recognition

Asset Impairments

•a significant decrease in the market price of an asset or asset group;

•a significant adverse change in the extent or manner in which an asset or asset group is being used or in its physical condition;

•a significant adverse change in legal factors or in the business climate that could affect the value of an asset or asset group, including an adverse action or assessment by a regulator;

•an accumulation of costs significantly in excess of the amount originally expected for the acquisition or construction of a long-lived asset;

•a current expectation that, more likely than not, a long-lived asset or asset group will be sold or otherwise disposed of significantly before the end of its previously estimated useful life; or

•an impairment of goodwill at a reporting unit.

Goodwill. We annually assess goodwill for impairment during the fourth quarter of our fiscal year or more frequently if events or circumstances indicate that impairment may exist.

•a significant adverse change in legal status or in the business climate;

•an adverse action or assessment by a regulator;

•a more likely than not expectation that an operating segment or a significant portion thereof will be sold; or

•the testing for recoverability of a significant asset group within the operating segment.

Defined Benefit Pension Plan

Stock-Based Compensation

Earnings per Share

Subsequent Events

Fair Value Measurement

Assets and Liabilities Accounted for at Fair Value on a Recurring Basis

Segment Reporting

We report selected information about our reportable operating segments in a manner consistent with that used for internal management reporting. We classify our solid waste operations on a geographic basis through three regional operating segments, our Eastern, Western and Mid-Atlantic regions. The Mid-Atlantic region, which was formed as a result of the GFL Acquisition on June 30, 2023, commenced operations on July 1, 2023. Revenues associated with our solid waste operations are derived mainly from solid waste collection and disposal services, including landfill, transfer station and transportation services, landfill gas-to-energy services, and processing services in the eastern United States. Our Resource Solutions operating segment leverages our core competencies in materials processing, industrial recycling, organics and resource management service offerings to deliver a comprehensive solution for our larger commercial, municipal, institutional and industrial customers that have more diverse waste and recycling needs. Revenues associated with our Resource Solutions are comprised of processing services and non-processing services, which we refer to as our National Accounts business. Revenues from processing services are derived from customers in the form of processing fees, tipping fees, commodity sales, and organic material sales. Revenues from our National Accounts business are derived from brokerage services and overall resource management services providing a wide range of environmental services and resource management solutions to large and complex organizations, as well as traditional collection, disposal and recycling services provided to large account multi-site customers. Legal, tax, information technology, human resources, certain finance and accounting and other administrative functions are included in our Corporate Entities segment, which is not a reportable operating segment. Corporate Entities results reflect those costs not allocated to our reportable operating segments.

OTHER ITEMS AND CHARGES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Unusual or Infrequent Items, or Both [Abstract]
Legal settlement	$ 6,150	$ 0	$ 0
Landfill capping charge - veneer failure	3,870	0	0
Expense from acquisition activities	15,038	4,613	5,304
Environmental remediation charge	$ 0	$ 759	$ 924

GOODWILL AND INTANGIBLE ASSETS (Tables)

12 Months Ended

Dec. 31, 2023

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Activity and Balances Related to Goodwill by Reporting Segment

A summary of the activity and balances related to goodwill by reportable operating segment is as follows:


	December 31, 2022		Acquisitions		Measurement Period Adjustments		December 31, 2023
Eastern	$	52,406	$	21,487	$	—	$	73,893
Western	183,286		101,717		53		285,056
Mid-Atlantic	—		332,247		—		332,247
Resource Solutions	38,766		5,708		—		44,474

Total	$	274,458	$	461,159	$	53	$	735,670


	December 31, 2021		Acquisitions		Measurement Period Adjustments		December 31, 2022
Eastern	$	52,072	$	93	$	241	$	52,406
Western	163,728		18,908		650		183,286
Mid-Atlantic	—		—		—		—
Resource Solutions	17,060		21,706		—		38,766

Total	$	232,860	$	40,707	$	891	$	274,458

Schedule of Components of Intangible Assets

A summary of intangible assets is as follows:


	Covenants Not-to-Compete		Customer Relationships		Trade Names		Total
Balance, December 31, 2023
Intangible assets	$	62,173	$	272,571	$	12,725	$	347,469
Less accumulated amortization	(26,645)		(72,227)		(7,168)		(106,040)
	$	35,528	$	200,344	$	5,557	$	241,429


	Covenants Not-to-Compete		Customer Relationships		Trade Names		Total
Balance, December 31, 2022
Intangible assets	$	31,201	$	127,179	$	8,405	$	166,785
Less accumulated amortization	(24,129)		(46,162)		(4,711)		(75,002)
	$	7,072	$	81,017	$	3,694	$	91,783

Schedule of Estimated Future Amortization Expense

Based on the amortizable intangible assets recorded in the consolidated balance sheets at December 31, 2023, intangible amortization expense for each of the next five fiscal years and thereafter is estimated as follows:




Fiscal year ending December 31, 2024	$	47,387
Fiscal year ending December 31, 2025	$	43,388
Fiscal year ending December 31, 2026	$	38,645
Fiscal year ending December 31, 2027	$	34,149
Fiscal year ending December 31, 2028	$	29,166
Thereafter	$	48,694

- Definition

Tabular disclosure of goodwill by reportable segment and in total which includes a rollforward schedule.

+ References

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+ Details

FAIR VALUE OF FINANCIAL INSTRUMENTS (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Assets:
Restricted investment securities - landfill closure	$ 2,203	$ 1,900
Liabilities:
Derivative Asset, Statement Of Financial Position Extensible Enumeration, Not Disclosed Flag	Interest rate swaps	Interest rate swaps
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Recurring
Assets:
Interest rate swaps		$ 0
Total assets	$ 2,203	1,900
Liabilities:
Contingent consideration - acquisition		0
Total liabilities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Recurring \| Interest rate swaps
Assets:
Interest rate swaps	0
Liabilities:
Interest rate swaps	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Recurring \| Landfills
Assets:
Restricted investment securities - landfill closure	2,203	1,900
Significant Other Observable Inputs (Level 2) \| Recurring
Assets:
Interest rate swaps		11,806
Total assets	10,364	11,806
Liabilities:
Contingent consideration - acquisition		0
Total liabilities	11,762	0
Significant Other Observable Inputs (Level 2) \| Recurring \| Interest rate swaps
Assets:
Interest rate swaps	10,364
Liabilities:
Interest rate swaps	11,762	0
Significant Other Observable Inputs (Level 2) \| Recurring \| Landfills
Assets:
Restricted investment securities - landfill closure	0	0
Significant Unobservable Inputs (Level 3) \| Recurring
Assets:
Interest rate swaps		0
Total assets	0	0
Liabilities:
Contingent consideration - acquisition		965
Total liabilities	0	965
Contingent consideration, decrease for reversal of contingency	965
Significant Unobservable Inputs (Level 3) \| Recurring \| Interest rate swaps
Assets:
Interest rate swaps	0
Liabilities:
Interest rate swaps	0	0
Significant Unobservable Inputs (Level 3) \| Recurring \| Landfills
Assets:
Restricted investment securities - landfill closure	$ 0	$ 0

DEBT - Loss from Termination of Bridge Financing (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Loss from termination of bridge financing	$ 8,191	$ 0	$ 0
GFL Environmental Inc
Debt Instrument [Line Items]
Loss from termination of bridge financing	3,718
Twin Bridges Acquisition
Debt Instrument [Line Items]
Loss from termination of bridge financing	$ 4,473

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details

OTHER ITEMS AND CHARGES (Tables)

12 Months Ended

Dec. 31, 2023

Unusual or Infrequent Items, or Both [Abstract]

Schedule of Southbridge Landfill Closure Charge, Net

Accordingly, in fiscal years 2023, 2022 and 2021, we recorded charges associated with the closure of the Southbridge Landfill as follows:


	Fiscal Year Ended December 31,
	2023		2022		2021
Legal and transaction costs (1)	$	412	$	684	$	868
Contract settlement charge (2)	—		—		572
Landfill closure project charge (credit) (3)	55		752		(944)





Southbridge Landfill closure charge, net	$	467	$	1,436	$	496

(1)We incurred legal costs as well as other transaction costs associated with various matters as part of the Southbridge Landfill closure.

(2)We updated the cost estimates associated with a contract settlement charge associated with the Southbridge Landfill closure and the remaining future obligations due to the Town of Southbridge under the landfill operating agreement with the Town of Southbridge.

(3)We recorded a landfill closure project charge (credit) each fiscal year associated with revised costs under the closure plan at Southbridge Landfill.

DEBT - Components of Debt (Details) - USD ($)	12 Months Ended
DEBT - Components of Debt (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Weighted-average discount rate - finance leases	4.00%
Finance leases maturing through December 2107; bearing interest at a weighted average of 4.0%	$ 53,066,000	$ 49,813,000
Principal amount of debt	1,054,546,000	603,477,000
Less—unamortized discount and debt issuance costs	11,103,000	9,494,000
Debt less unamortized debt issuance costs	1,043,443,000	593,983,000
Less—current maturities of debt	35,781,000	8,968,000
Debt, less current portion	$ 1,007,662,000	$ 585,015,000
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Debt, less current portion	Debt, less current portion
Secured Debt \| Term Loan A Facility ("Term Loan Facility") due December 2026; bearing interest at 7.083% as of December 31, 2023
Debt Instrument [Line Items]
Principal amount of debt	$ 350,000,000	$ 350,000,000
Secured Debt \| Term Loan A Facility ("2023 Term Loan Facility") due December 2026; bearing interest at 7.581% as of December 31, 2023
Debt Instrument [Line Items]
Principal amount of debt	419,250,000	0
Line of Credit \| Revolving Credit Facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.725%
Debt Instrument [Line Items]
Principal amount of debt	0	6,000,000
Unsecured Debt
Debt Instrument [Line Items]
Principal amount of debt	$ 232,000,000
Unsecured Debt \| New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014 ("New York Bonds 2014R-1") due December 2044 - fixed rate interest period bearing interest at 2.875% through December 2029
Debt Instrument [Line Items]
Stated interest rate	2.875%
Principal amount of debt	$ 25,000,000	25,000,000
Unsecured Debt \| New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014R-2 ("New York Bonds 2014R-2") due December 2044 - fixed rate interest period bearing interest at 3.125% through May 2026
Debt Instrument [Line Items]
Stated interest rate	3.125%
Principal amount of debt	$ 15,000,000	15,000,000
Unsecured Debt \| New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2020 ("New York Bonds 2020") due September 2050 - fixed rate interest period bearing interest at 2.750% through September 2025
Debt Instrument [Line Items]
Stated interest rate	2.75%
Principal amount of debt	$ 40,000,000	40,000,000
Unsecured Debt \| New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2020R-2 ("New York Bonds 2020R-2") due September 2050 - fixed rate interest period bearing interest at 5.125% through September 2030
Debt Instrument [Line Items]
Stated interest rate	5.125%
Principal amount of debt	$ 35,000,000	0
Unsecured Debt \| Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2005R-3 ("FAME Bonds 2005R-3") due January 2025 - fixed rate interest period bearing interest at 5.25% through January 2025
Debt Instrument [Line Items]
Stated interest rate	5.25%
Principal amount of debt	$ 25,000,000	25,000,000
Unsecured Debt \| Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-1 ("FAME Bonds 2015R-1") due August 2035 - fixed rate interest period bearing interest at 5.125% through July 2025
Debt Instrument [Line Items]
Stated interest rate	5.125%
Principal amount of debt	$ 15,000,000	15,000,000
Unsecured Debt \| Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-2 ("FAME Bonds 2015R-2") due August 2035 - fixed rate interest period bearing interest at 4.375% through July 2025
Debt Instrument [Line Items]
Stated interest rate	4.375%
Principal amount of debt	$ 15,000,000	15,000,000
Unsecured Debt \| Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2013 ("Vermont Bonds 2013") due April 2036 - fixed rate interest period bearing interest at 4.625% through April 2028
Debt Instrument [Line Items]
Stated interest rate	4.625%
Principal amount of debt	$ 16,000,000	16,000,000
Unsecured Debt \| Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2022A-1 ("Vermont Bonds 2022A-1") due June 2052 - fixed rate interest period bearing interest at 5.00% through May 2027
Debt Instrument [Line Items]
Stated interest rate	5.00%
Principal amount of debt	$ 35,000,000	35,000,000
Unsecured Debt \| Business Finance Authority of the State of New Hampshire Solid Waste Disposal Revenue Bonds Series 2013 ("New Hampshire Bonds") due April 2029 - fixed rate interest period bearing interest at 2.95% through April 2029
Debt Instrument [Line Items]
Stated interest rate	2.95%
Principal amount of debt	$ 11,000,000	11,000,000
Notes payable maturing through March 2025; bearing interest up to 8.1%
Debt Instrument [Line Items]
Weighted average interest rate	8.10%
Principal amount of debt	$ 230,000	$ 664,000
SOFR \| Secured Debt \| Term Loan A Facility ("Term Loan Facility") due December 2026; bearing interest at 7.083% as of December 31, 2023
Debt Instrument [Line Items]
Stated interest rate	7.083%
SOFR \| Secured Debt \| Term Loan A Facility ("2023 Term Loan Facility") due December 2026; bearing interest at 7.581% as of December 31, 2023
Debt Instrument [Line Items]
Stated interest rate	7.581%
SOFR \| Line of Credit \| Revolving Credit Facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.725%
Debt Instrument [Line Items]
Basis spread on variable rate	1.725%

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash Flows from Operating Activities:
Net income	$ 25,399	$ 53,079	$ 41,100
net income to net cash provided by operating activities:
Depreciation and amortization	170,705	126,351	103,590
Interest accretion on landfill and environmental remediation liabilities	9,885	8,008	7,324
Amortization of debt issuance costs	2,962	1,903	2,288
Stock-based compensation	9,084	8,155	11,551
Operating lease right-of-use assets expense	15,318	13,804	13,827
Disposition of assets, other items and charges, net	708	737	1,055
Loss from termination of bridge financing	8,191	0	0
Landfill capping charge - veneer failure	3,021	0	0
Deferred income taxes	7,392	16,527	15,073
Changes in assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable	(39,436)	(7,101)	(7,422)
Landfill operating lease contract expenditures	(5,496)	(5,486)	(5,655)
Accounts payable	41,592	11,075	13,888
Prepaid expenses, inventories and other assets	(8,172)	(11,054)	(6,343)
Accrued expenses, contract liabilities and other liabilities	(8,061)	1,316	(7,539)
Net cash provided by operating activities	233,092	217,314	182,737
Cash Flows from Investing Activities:
Acquisitions, net of cash acquired	(851,839)	(78,197)	(170,647)
Additions to property and equipment	(154,907)	(130,960)	(123,295)
Proceeds from sale of cost method investment	0	1,637	0
Proceeds from sale of property and equipment	1,110	600	788
Net cash used in investing activities	(1,005,636)	(206,920)	(293,154)
Cash Flows from Financing Activities:
Proceeds from debt borrowings	465,000	88,200	3,701
Principal payments on debt	(26,257)	(59,211)	(10,305)
Payments of debt issuance costs	(12,759)	(1,232)	(3,684)
Payments of contingent consideration	0	(1,000)	0
Proceeds from the exercise of share based awards	89	192	172
Proceeds from the public offering of Class A Common Stock	496,231	0	0
Net cash provided by (used in) financing activities	922,304	26,949	(10,116)
Net increase (decrease) in cash and cash equivalents	149,760	37,343	(120,533)
Cash and cash equivalents, beginning of period	71,152	33,809	154,342
Cash and cash equivalents, end of period	220,912	71,152	33,809
Supplemental Disclosures of Cash Flow Information:
Interest	43,588	21,003	19,025
Income tax payments, net	10,109	2,798	1,438
Supplemental Disclosures of Non-Cash Investing and Financing Activities:
Non-current assets acquired through long-term financing obligations	$ 12,322	$ 11,919	$ 20,753

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Intangible Assets and Investments in Unconsolidated Entities (Detail) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Intangible assets, useful life	10 years
Investments under equity method of accounting	$ 0	$ 0
Cost method investments	$ 10,967,000	$ 10,967,000

FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS

12 Months Ended

Dec. 31, 2023

Asset Retirement Obligation Disclosure [Abstract]

FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS

Accrued final capping, closure and post-closure costs include the current and non-current portion of costs associated with obligations for final capping closure and post-closure of our landfills. We estimate our future final capping, closure and post-closure costs in order to determine the final capping, closure and post-closure expense per ton of waste placed into each landfill as further described in Note 3, Summary of Significant Accounting Policies. The anticipated time frame for paying these costs varies based on the remaining useful life of each landfill, as well as the duration of the post-closure monitoring period.

The changes to accrued final capping, closure and post-closure liabilities are as follows:


	Fiscal Year Ended December 31,
	2023		2022
Beginning balance	$	113,678	$	86,914
Obligations incurred	5,447		4,857
Revisions in estimates (1)	14,030		18,415
Accretion expense	9,529		7,565
Obligations settled (2)	(11,801)		(4,073)
Write-off of capping payments (3)	3,021		—
Ending balance	$	133,904	$	113,678

(2)May include amounts paid and amounts that are being processed through accounts payable as a part of our disbursement cycle.

CONSOLIDATED BALANCE SHEETS (Parenthetical) $ in Thousands	12 Months Ended
CONSOLIDATED BALANCE SHEETS (Parenthetical) $ in Thousands	Dec. 31, 2023 USD ($) vote $ / shares shares	Dec. 31, 2022 USD ($) vote $ / shares shares
Accounts receivable - trade, allowance for credit losses \| $	$ 4,066	$ 3,016
Accumulated depreciation and amortization \| $	$ 1,167,541	$ 1,064,756
Class A Common Stock
Common stock, par value (in dollars per share) \| $ / shares	$ 0.01	$ 0.01
Common stock, authorized shares	100,000,000	100,000,000
Common stock, issued shares	57,007,000	50,704,000
Common stock, outstanding shares	57,007,000	50,704,000
Common stock, votes (in votes per share) \| vote	1
Class B Common Stock
Common stock, par value (in dollars per share) \| $ / shares	$ 0.01	$ 0.01
Common stock, authorized shares	1,000,000	1,000,000
Common stock, issued shares	988,000	988,000
Common stock, outstanding shares	988,000	988,000
Common stock, votes (in votes per share) \| vote	10	10

REVENUE RECOGNITION (Tables)

12 Months Ended

Dec. 31, 2023

Revenue from Contract with Customer [Abstract]

Schedule of Disaggregation of Revenue

A table of revenues disaggregated by service line and timing of revenue recognition by operating segment follows:

Fiscal Year Ended December 31, 2023


	Eastern		Western		Mid-Atlantic (1)		Resource Solutions		Total Revenues
Collection	$	266,991	$	358,883	$	84,716	$	—	$	710,590
Landfill	28,275		72,726		—		—		101,001
Transfer	65,401		56,630		924		—		122,955
Transportation	4,994		15,632		—		—		20,626
Landfill gas-to-energy	806		5,811		—		—		6,617
Processing	7,996		1,958		—		105,997		115,951
National Accounts	—		—		—		186,802		186,802
Total revenues	$	374,463	$	511,640	$	85,640	$	292,799	$	1,264,542

Transferred at a point-in-time	$	463	$	2,731	$	—	$	34,654	$	37,848
Transferred over time	374,000		508,909		85,640		258,145		1,226,694
Total revenues	$	374,463	$	511,640	$	85,640	$	292,799	$	1,264,542

(1)Operations under the Mid-Atlantic region commenced July 1, 2023.

Fiscal Year Ended December 31, 2022


	Eastern		Western		Mid-Atlantic (1)		Resource Solutions		Total Revenues
Collection	$	233,043	$	306,544	$	—	$	—	$	539,587
Landfill	27,301		70,241		—		—		97,542
Transfer	65,800		44,762		—		—		110,562
Transportation	5,619		14,248		—		—		19,867
Landfill gas-to-energy	925		6,594		—		—		7,519
Processing	7,370		2,764		—		119,045		129,179
National Accounts	—		—		—		180,833		180,833
Total revenues	$	340,058	$	445,153	$	—	$	299,878	$	1,085,089

Transferred at a point-in-time	$	462	$	2,138	$	—	$	52,735	$	55,335
Transferred over time	339,596		443,015		—		247,143		1,029,754
Total revenues	$	340,058	$	445,153	$	—	$	299,878	$	1,085,089

(1)Operations under the Mid-Atlantic region commenced July 1, 2023.

Fiscal Year Ended December 31, 2021


	Eastern		Western		Mid-Atlantic (1)		Resource Solutions		Total Revenues
Collection	$	175,816	$	266,869	$	—	$	—	$	442,685
Landfill	25,241		66,732		—		—		91,973
Transfer	53,882		37,400		—		—		91,282
Transportation	1,683		12,047		—		—		13,730
Landfill gas-to-energy	1,052		4,086		—		—		5,138
Processing	6,895		2,386		—		93,323		102,604
National Accounts	—		—		—		141,799		141,799
Total revenues	$	264,569	$	389,520	$	—	$	235,122	$	889,211

Transferred at a point-in-time	$	166	$	1,719	$	—	$	63,666	$	65,551
Transferred over time	264,403		387,801		—		171,456		823,660
Total revenues	$	264,569	$	389,520	$	—	$	235,122	$	889,211

(1)Operations under the Mid-Atlantic region commenced July 1, 2023.

ACCOUNTS RECEIVABLE, NET OF ALLOWANCE FOR CREDIT LOSSES

12 Months Ended

Dec. 31, 2023

Credit Loss [Abstract]

ACCOUNTS RECEIVABLE, NET OF ALLOWANCE FOR CREDIT LOSSES

A summary of the changes to allowance for credit losses follows:


	Fiscal Year Ended December 31,
	2023		2022		2021
Balance at beginning of period	$	3,016	$	3,276	$	2,333

Additions - charged to expense	2,468		1,893		1,896
Deductions - write offs charged against the allowance, net of recoveries	(1,418)		(2,153)		(953)
Balance at end of period	$	4,066	$	3,016	$	3,276

- Definition

The entire disclosure for credit loss on financial instrument measured at amortized cost basis, net investment in lease, off-balance sheet credit exposure, and available-for-sale debt security.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-42

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
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-Section 50
-Paragraph 44
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-44

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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+ Details

GOODWILL AND INTANGIBLE ASSETS

12 Months Ended

Dec. 31, 2023

Goodwill and Intangible Assets Disclosure [Abstract]

GOODWILL AND INTANGIBLE ASSETS

A summary of the activity and balances related to goodwill by reportable operating segment is as follows:


	December 31, 2022		Acquisitions		Measurement Period Adjustments		December 31, 2023
Eastern	$	52,406	$	21,487	$	—	$	73,893
Western	183,286		101,717		53		285,056
Mid-Atlantic	—		332,247		—		332,247
Resource Solutions	38,766		5,708		—		44,474

Total	$	274,458	$	461,159	$	53	$	735,670


	December 31, 2021		Acquisitions		Measurement Period Adjustments		December 31, 2022
Eastern	$	52,072	$	93	$	241	$	52,406
Western	163,728		18,908		650		183,286
Mid-Atlantic	—		—		—		—
Resource Solutions	17,060		21,706		—		38,766

Total	$	232,860	$	40,707	$	891	$	274,458

A summary of intangible assets is as follows:


	Covenants Not-to-Compete		Customer Relationships		Trade Names		Total
Balance, December 31, 2023
Intangible assets	$	62,173	$	272,571	$	12,725	$	347,469
Less accumulated amortization	(26,645)		(72,227)		(7,168)		(106,040)
	$	35,528	$	200,344	$	5,557	$	241,429


	Covenants Not-to-Compete		Customer Relationships		Trade Names		Total
Balance, December 31, 2022
Intangible assets	$	31,201	$	127,179	$	8,405	$	166,785
Less accumulated amortization	(24,129)		(46,162)		(4,711)		(75,002)
	$	7,072	$	81,017	$	3,694	$	91,783

Intangible amortization expense for fiscal years 2023, 2022 and 2021 was $31,037, $16,593 and $10,953, respectively.




Fiscal year ending December 31, 2024	$	47,387
Fiscal year ending December 31, 2025	$	43,388
Fiscal year ending December 31, 2026	$	38,645
Fiscal year ending December 31, 2027	$	34,149
Fiscal year ending December 31, 2028	$	29,166
Thereafter	$	48,694

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net income	$ 25,399	$ 53,079	$ 41,100

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
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-Name Accounting Standards Codification
-Section S99
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
-Paragraph 30
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 30: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 31: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-60B

Reference 32: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 33: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 34: http://www.xbrl.org/2003/role/disclosureRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483499/205-20-50-7

Reference 35: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-28

Reference 36: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1A

Reference 37: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1B

Reference 38: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(20))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 39: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(22))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

+ Details

DEBT - Summary of Cash Flow Hedges (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Accumulated other comprehensive (loss) income, net of tax	$ (1,080)	$ 7,542
Designated as hedging instrument \| Interest rate swaps
Debt Instrument [Line Items]
Cash flow hedge derivatives, assets	10,364	11,806
Designated as hedging instrument \| Interest rate swaps \| Accumulated income (loss), net, cash flow hedge
Debt Instrument [Line Items]
Accumulated other comprehensive income (loss), before tax	(1,398)	11,806
Accumulated other comprehensive income (loss), tax	318	(4,264)
Accumulated other comprehensive (loss) income, net of tax	(1,080)	7,542
Other current assets \| Designated as hedging instrument \| Interest rate swaps
Debt Instrument [Line Items]
Cash flow hedge derivatives, assets	5,951	4,345
Other non-current assets \| Designated as hedging instrument \| Interest rate swaps
Debt Instrument [Line Items]
Cash flow hedge derivatives, assets	4,413	7,461
Other long-term liabilities \| Designated as hedging instrument \| Interest rate swaps
Debt Instrument [Line Items]
Cash flow hedge derivatives, liabilities	$ 11,762	$ 0

INCOME TAXES

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

INCOME TAXES

A summary of the provision for income taxes is as follows:


	Fiscal Year Ended December 31,
	2023		2022		2021
Federal


Deferred	8,155		15,645		12,356
	8,155		15,645		12,356
State
Current	4,385		5,362		1,873

Deferred	(894)		880		2,717
	3,491		6,242		4,590
Provision for income taxes	$	11,646	$	21,887	$	16,946

On a periodic basis, we reassess the valuation allowance on our deferred income tax assets, weighing positive and negative evidence to assess the recoverability of the deferred tax assets. In the fourth quarter of fiscal year 2020, we assessed the valuation allowance and considered positive evidence, including significant cumulative consolidated income over the three years ended December 31, 2020, revenue growth and expectations of future profitability, and negative evidence, including the impact of a negative change in the economic climate, significant risks and uncertainties in the business and restrictions on tax loss utilization in certain state jurisdictions. After assessing both the positive evidence and the negative evidence, we determined it was more likely than not that the majority of our deferred tax assets would be realized in the future and released the valuation allowance on the majority of our net operating loss carryforwards and other deferred tax assets as of December 31, 2020, resulting in a benefit from income taxes of $61,317. Following reassessment in fiscal years 2021, 2022 and 2023, our judgement with regard to the realizability of our deferred tax assets remains consistent. As of December 31, 2023, we maintained a valuation allowance of $5,580 primarily related to deferred tax assets that would generate capital losses when realized and deferred tax assets related to certain state jurisdictions.

In assessing the realizability of carryforwards and other deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. We adjust the valuation allowance in the period management determines it is more likely than not that deferred tax assets will or will not be realized. The change in the valuation allowance for fiscal year 2023 was an increase of $912. In determining the need for a valuation allowance, we have assessed the available means of recovering deferred tax assets, including the ability to carryback net operating losses, the existence of reversing temporary differences, and available sources of future taxable income. We have also considered the ability to implement certain strategies, such as a potential sale of assets that would, if necessary, be implemented to accelerate taxable income and use expiring deferred tax assets.

The differences in the provision for income taxes and the amounts determined by applying the Federal statutory rate to income before income taxes are as follows:


	Fiscal Year Ended December 31,
	2023			2022			2021
Federal statutory rate	21		%	21		%	21		%
Tax at statutory rate	$	7,779		$	15,743		$	12,190
State income taxes, net of federal benefit	1,383			6,087			3,868
Change in valuation allowance	912			(1,425)			(388)
Federal effect of change in state valuation allowance	(312)			282			74
Non-deductible officer compensation	996			1,300			1,338
Non-deductible expenses	809			782			322

Deductible stock awards	(963)			(627)			(363)
Tax credits	(60)			(83)			(153)
Reversal of disproportionate tax effects in other comprehensive (loss) income	938			—			—



Other, net	164			(172)			58
Provision for income taxes	$	11,646		$	21,887		$	16,946

Deferred income taxes reflect the impact of temporary differences between the amounts of assets and liabilities recognized for financial reporting purposes and such amounts recognized for income tax purposes. A summary of deferred tax assets and liabilities is as follows:


	December 31,
	2023		2022
Deferred tax assets:
Accrued expenses and reserves	$	49,339	$	43,437
Net operating loss carryforwards	30,165		13,398
General business and state tax credit carryforwards	6,862		6,987
Interest expense limitation	6,690		—
Stock awards	2,690		2,728
Unrealized loss on swaps	375		—



Other	1,567		2,419
Total deferred tax assets	97,688		68,969
Less: valuation allowance	(5,580)		(4,668)
Total deferred tax assets after valuation allowance	92,108		64,301
Deferred tax liabilities:
Tax over book depreciation of property and equipment	(58,927)		(21,561)
Amortization of intangibles	(22,540)		(17,252)
Unrealized gain on swaps	—		(3,022)

Other	(44)		—
Total deferred tax liabilities	(81,511)		(41,835)
Net deferred tax asset	$	10,597	$	22,466

The net deferred tax asset at December 31, 2023 is reflected on the consolidated balance sheet as a long-term deferred federal and state tax asset of $11,224 and a long-term deferred state tax liability of $(627).

As of December 31, 2023, we have, for federal income tax purposes, net operating loss carryforwards of approximately $7,152 that expire in the fiscal years ending December 31, 2032 through 2037 and $125,665, which do not expire. We have state net operating loss carryforwards of approximately $28,262 that expire in the fiscal years ending December 31, 2024 through 2043 or that do not expire in certain jurisdictions. In addition, we have $6,722 general business credit carryforwards which expire in the fiscal years ending December 31, 2024 through 2043 and $176 state credit carryforwards which expire in fiscal year ending December 31, 2039. Sections 382 and 383 of the Internal Revenue Code can limit the amount of net operating loss and credit carryforwards which may be used in a tax year in the event of certain stock ownership changes. With the exception of $1,756 federal net operating losses we acquired through acquisitions, we are not currently subject to these limitations but could become subject to them if there were significant changes in the ownership of our stock.

The provisions of FASB ASC 740-10-25-5 prescribe the minimum recognition threshold that a tax position is required to meet before being recognized in the financial statements. Additionally, FASB ASC 740-10-25-5 provides guidance on derecognition, measurement, classification, interest and penalties, accounting in interim periods, disclosure and transition. Under FASB ASC 740-10-25-5, an entity may only recognize or continue to recognize tax positions that meet a “more likely than not” threshold. To the extent interest and penalties are not assessed with respect to uncertain tax positions, amounts accrued are reflected as a reduction of the overall income tax provision. As of December 31, 2023 and 2022, we did not have any uncertain tax positions.

We are subject to U.S. federal income tax, as well as the income tax of multiple state jurisdictions. For federal tax purposes, income tax returns from years ending 2020 through 2023 are open for assessment. Tax years 1998 through 2019 are open for examination to the extent of any NOLs or credits that have been carried forward from those years.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 270
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

STOCKHOLDERS' EQUITY - Summary of Stock Option Activity (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares shares
Stock Options
Outstanding, beginning balance (in shares) \| shares	129,000
Granted (in shares) \| shares	18,000
Exercised (in shares) \| shares	(18,000)
Forfeited or expired (in shares) \| shares	0
Outstanding, ending balance (in shares) \| shares	129,000
Exercisable (in shares) \| shares	49,000
Weighted Average Exercise Price
Outstanding, beginning balance (in dollars per share) \| $ / shares	$ 55.60
Granted (in dollars per share) \| $ / shares	79.72
Exercised (in dollars per share) \| $ / shares	4.88
Forfeited or expired (in dollars per share) \| $ / shares	0
Outstanding, ending balance (in dollars per share) \| $ / shares	66.03
Exercisable (in dollars per share) \| $ / shares	$ 40.60
Weighted average remaining contractual term, outstanding	7 years 6 months
Weighted average remaining contractual term, exercisable	5 years 2 months 12 days
Aggregate intrinsic value, outstanding \| $	$ 2,504
Aggregate intrinsic value, exercisable \| $	$ 2,177

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Estimated Useful Lives of Assets (Detail)	Dec. 31, 2023
Minimum \| Buildings and improvements
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	10 years
Minimum \| Machinery and equipment
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	5 years
Minimum \| Rolling stock
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	5 years
Minimum \| Containers
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	5 years
Minimum \| Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	3 years
Maximum \| Buildings and improvements
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	30 years
Maximum \| Machinery and equipment
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	10 years
Maximum \| Rolling stock
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	10 years
Maximum \| Containers
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	12 years
Maximum \| Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property plant and equipment, estimated useful life	8 years

DEBT (Tables)

12 Months Ended

Dec. 31, 2023

Debt Disclosure [Abstract]

Schedule of Debt

A summary of debt is as follows:


	December 31,
	2023		2022
Senior Secured Credit Facility:
Term Loan A Facility ("Term Loan Facility") due December 2026; bearing interest at 7.083% as of December 31, 2023	$	350,000	$	350,000
Term Loan A Facility ("2023 Term Loan Facility") due December 2026; bearing interest at 7.581% as of December 31, 2023	419,250		—
Revolving Credit Facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.725%	—		6,000
Tax-Exempt Bonds:
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014 ("New York Bonds 2014R-1") due December 2044 - fixed rate interest period bearing interest at 2.875% through December 2029	25,000		25,000
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014R-2 ("New York Bonds 2014R-2") due December 2044 - fixed rate interest period bearing interest at 3.125% through May 2026	15,000		15,000
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2020 ("New York Bonds 2020") due September 2050 - fixed rate interest period bearing interest at 2.750% through September 2025	40,000		40,000
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2020R-2 ("New York Bonds 2020R-2") due September 2050 - fixed rate interest period bearing interest at 5.125% through September 2030	35,000		—
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2005R-3 ("FAME Bonds 2005R-3") due January 2025 - fixed rate interest period bearing interest at 5.25% through January 2025	25,000		25,000
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-1 ("FAME Bonds 2015R-1") due August 2035 - fixed rate interest period bearing interest at 5.125% through July 2025	15,000		15,000
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-2 ("FAME Bonds 2015R-2") due August 2035 - fixed rate interest period bearing interest at 4.375% through July 2025	15,000		15,000
Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2013 ("Vermont Bonds 2013") due April 2036 - fixed rate interest period bearing interest at 4.625% through April 2028	16,000		16,000
Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2022A-1 ("Vermont Bonds 2022A-1") due June 2052 - fixed rate interest period bearing interest at 5.00% through May 2027	35,000		35,000
Business Finance Authority of the State of New Hampshire Solid Waste Disposal Revenue Bonds Series 2013 ("New Hampshire Bonds") due April 2029 - fixed rate interest period bearing interest at 2.95% through April 2029	11,000		11,000
Other:
Finance leases maturing through December 2107; bearing interest at a weighted average of 4.0%	53,066		49,813
Notes payable maturing through March 2025; bearing interest up to 8.1%	230		664
Principal amount of debt	1,054,546		603,477
Less—unamortized debt issuance costs	11,103		9,494
Debt less unamortized debt issuance costs	1,043,443		593,983
Less—current maturities of debt	35,781		8,968
Debt, less current portion	$	1,007,662	$	585,015

The Credit Facility shall bear interest, at our election, at Term SOFR, including a secured overnight financing rate adjustment of 10 basis points, or at a base rate, in each case plus or minus any sustainable rate adjustment of up to positive or negative 4.0 basis points per annum, plus an applicable interest rate margin based upon our consolidated net leverage ratio as follows:

Term SOFR Loans

Base Rate Loans

Term Loan Facility

1.125% to 2.125%

0.125% to 1.125%

Revolving Credit Facility

1.125% to 2.125%

0.125% to 1.125%

2023 Term Loan Facility

1.625% to 2.625%

0.625% to 1.625%

Schedule of Components of Interest Expense

The components of interest expense are as follows:


	Fiscal Year Ended December 31,
	2023		2022		2021
Interest expense on long-term debt and finance leases	$	44,836	$	21,691	$	19,201
Amortization of debt issuance costs (1)	2,962		1,903		2,288
Letter of credit fees	423		458		458
Less: capitalized interest	(643)		(330)		(718)
Total interest expense	$	47,578	$	23,722	$	21,229

(1)Includes interest expense related to a short-term secured bridge financing entered into in connection with the GFL Acquisition and interest expense related to a short-term unsecured bridge financing entered into in connection with the Twin Bridges Acquisition of $395 and $101, respectively, during the fiscal year ended December 31, 2023.

Schedule of Notional Amounts

A summary of the changes to the notional amount of interest rate derivative agreements follows:


	Active		Forward Starting		Total
Balance, December 31, 2021	$	195,000	$	85,000	$	280,000

Commencements	65,000		(65,000)		—
Maturities	(70,000)		—		(70,000)
Balance, December 31, 2022 (1)	190,000		20,000		210,000
Additions	390,000		—		390,000
Commencements	20,000		(20,000)		—
Maturities	(85,000)		—		(85,000)
Balance, December 31, 2023 (2)	$	515,000	$	—	$	515,000

(1)These agreements mature between May 2023 and May 2028 and state that we receive interest based on 1-month LIBOR, restricted by a 0.0% floor in some instances, and pay interest at a weighted average rate of approximately 2.11%.

(2)These agreements mature between February 2026 and June 2028 and state that we receive interest based on Term SOFR, restricted by a 0.0% floor, and pay interest at a weighted average rate of approximately 3.60%.

Schedule of Cash Flow Hedges Related to Derivative Instruments

A summary of the effect of cash flow hedges related to derivative instruments on the consolidated balance sheets follows:


		Fair Value
	Balance Sheet Location	December 31, 2023		December 31, 2022
Interest rate swaps	Other current assets	$	5,951	$	4,345
Interest rate swaps	Other non-current assets	4,413		7,461
Total		$	10,364	$	11,806


Interest rate swaps	Other long-term liabilities	$	11,762	$	—


Interest rate swaps	Accumulated other comprehensive (loss) income, net	$	(1,398)	$	11,806
Interest rate swaps - tax effect	Accumulated other comprehensive (loss) income, net	318		(4,264)
		$	(1,080)	$	7,542

Schedule of Future Maturities of Debt

Aggregate principal maturities of debt as of December 31, 2023 for each of the next five fiscal years and thereafter are as follows:



Fiscal year ending December 31, 2024	$	35,781
Fiscal year ending December 31, 2025	66,455
Fiscal year ending December 31, 2026	724,288
Fiscal year ending December 31, 2027	6,965
Fiscal year ending December 31, 2028	6,566
Thereafter	214,491
	$	1,054,546

ACCOUNTS RECEIVABLE, NET OF ALLOWANCE FOR CREDIT LOSSES (Tables)

12 Months Ended

Dec. 31, 2023

Credit Loss [Abstract]

Schedule of Changes to Allowance for Credit Losses

A summary of the changes to allowance for credit losses follows:


	Fiscal Year Ended December 31,
	2023		2022		2021
Balance at beginning of period	$	3,016	$	3,276	$	2,333

Additions - charged to expense	2,468		1,893		1,896
Deductions - write offs charged against the allowance, net of recoveries	(1,418)		(2,153)		(953)
Balance at end of period	$	4,066	$	3,016	$	3,276

INCOME TAXES - Schedule of Difference in Benefit for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Federal statutory rate	21.00%	21.00%	21.00%
Tax at statutory rate	$ 7,779	$ 15,743	$ 12,190
State income taxes, net of federal benefit	1,383	6,087	3,868
Change in valuation allowance	912	(1,425)	(388)	$ (61,317)
Federal effect of change in state valuation allowance	(312)	282	74
Non-deductible officer compensation	996	1,300	1,338
Non-deductible expenses	809	782	322
Deductible stock awards	(963)	(627)	(363)
Tax credits	(60)	(83)	(153)
Reversal of disproportionate tax effects in other comprehensive (loss) income	938	0	0
Other, net	164	(172)	58
Provision for income taxes	$ 11,646	$ 21,887	$ 16,946

BASIS OF PRESENTATION (Detail)		12 Months Ended
BASIS OF PRESENTATION (Detail)	Jun. 30, 2023 subsidiary	Dec. 31, 2023 state segment
Segment Reporting Information [Line Items]
Number of states in which entity operates \| state		9
Number of wholly owned subsidiaries acquired \| subsidiary	4
Solid waste operations
Segment Reporting Information [Line Items]
Operating segments \| segment		3

OTHER ITEMS AND CHARGES

12 Months Ended

Dec. 31, 2023

Unusual or Infrequent Items, or Both [Abstract]

OTHER ITEMS AND CHARGES

Legal Settlement

In fiscal year 2023, we recorded a charge of $6,150 accrued for in other accrued liabilities due to reaching an agreement at a mediation held on June 20, 2023 with the collective class members of a class action lawsuit relating to certain claims under the Fair Labor Standards Act of 1938 as well as state wage and hours laws. The settlement agreement was executed July 24, 2023 and has received court approval. See Note 13, Commitments and Contingencies for disclosure regarding our aggregate legal proceedings accrual.

Landfill Capping Charge - Veneer Failure

In fiscal year 2023, we recorded a charge of $3,870 consisting of both (i) the write-off of historical payments associated with capping work that has been deemed no longer viable due to a veneer failure and (ii) the related operating expenses incurred to clean up the affected capping material at the Ontario County Landfill that we operate. Engineering analysis is currently underway to determine root causes and responsibility for the event. See Note 10, Final Capping, Closure and Post-Closure Costs for disclosure over our remaining estimated costs associated with obligations for final capping closure and post-closure of our landfills.

Southbridge Landfill Closure Charge, Net

In the fiscal year ended December 31, 2017, we initiated a plan to cease operations of the Town of Southbridge, Massachusetts landfill (“Southbridge Landfill”) and later closed it in November 2018 when Southbridge Landfill reached its final capacity. Accordingly, in fiscal years 2023, 2022 and 2021, we recorded charges associated with the closure of the Southbridge Landfill as follows:


	Fiscal Year Ended December 31,
	2023		2022		2021
Legal and transaction costs (1)	$	412	$	684	$	868
Contract settlement charge (2)	—		—		572
Landfill closure project charge (credit) (3)	55		752		(944)





Southbridge Landfill closure charge, net	$	467	$	1,436	$	496

(1)We incurred legal costs as well as other transaction costs associated with various matters as part of the Southbridge Landfill closure.

(3)We recorded a landfill closure project charge (credit) each fiscal year associated with revised costs under the closure plan at Southbridge Landfill.

Expense from Acquisition Activities

In the fiscal years 2023, 2022 and 2021, we recognized expenses of $15,038, $4,613 and $5,304, respectively, comprised primarily of legal, consulting and other similar costs associated with the due diligence, acquisition and integration of acquired businesses, including the GFL Acquisition and the Twin Bridges Acquisition, in fiscal year 2023, or select development projects. See Note 5, Business Combinations for disclosure regarding acquisition activity.

Environmental Remediation Charge

In fiscal year 2022, we recorded a charge of $759 associated with the investigation of potential remediation at an inactive waste disposal site that adjoins one of the landfills we operate. In fiscal year 2021, we recorded a charge of $924 associated with a settlement agreement to conduct restoration of a stream bed on lands adjoining one of our landfills. See Note 13, Commitments and Contingencies for disclosure regarding environmental remediation liabilities.

DEBT - Fair Value of Debt (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Secured Debt \| Term Loan A Facility ("Term Loan Facility") due December 2026; bearing interest at 7.083% as of December 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Principal amount of debt	$ 350,000,000	$ 350,000,000
Secured Debt \| Term Loan A Facility ("2023 Term Loan Facility") due December 2026; bearing interest at 7.581% as of December 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Principal amount of debt	419,250,000	0
Line of Credit \| Revolving Credit Facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.725%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Principal amount of debt	0	$ 6,000,000
Fair Value \| Industrial Revenue Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt	226,756,000
Carrying Value \| Industrial Revenue Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt	$ 232,000,000

EARNINGS PER SHARE (Tables)

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

Schedule of Numerator and Denominator Used in Computation of Earnings per Share

A summary of the numerator and denominators used in the computation of earnings per share is as follows:


	Fiscal Year Ended December 31,
	2023		2022		2021
Numerator:
Net income	$	25,399	$	53,079	$	41,100
Denominator:
Class A common stock	57,007		50,704		50,423
Class B common stock	988		988		988

Unvested restricted stock awards	—		(1)		(2)
Effect of weighted average shares outstanding (1)	(2,821)		(68)		(97)
Basic weighted average common shares outstanding	55,174		51,623		51,312
Impact of potentially dilutive securities:
Dilutive effect of stock options and stock awards	100		144		203
Diluted weighted average common shares outstanding	55,274		51,767		51,515
Anti-dilutive potentially issuable shares	93		111		10

(1)The adjustment in fiscal year 2023 is primarily associated with the 6,053 shares of Class A common stock issued as part of the public offering completed on June 16, 2023. See Note 14, Stockholders’ Equity for disclosure regarding the public offering of Class A common stock.

DEBT - Summary of Notional Amounts (Details) - Cash Flow Hedging - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Total
Derivative, Notional Amount [Roll Forward]
Beginning balance	$ 210,000	$ 280,000
Additions	390,000
Commencements	0	0
Maturities	(85,000)	(70,000)
Ending balance	$ 515,000	210,000
Floor interest rate	0.00%
Weighted average percentage rate paid	3.60%
Active
Derivative, Notional Amount [Roll Forward]
Beginning balance	$ 190,000	195,000
Additions	390,000
Commencements	20,000	65,000
Maturities	(85,000)	(70,000)
Ending balance	515,000	$ 190,000
Floor interest rate		0.00%
Weighted average percentage rate paid		2.11%
Forward Starting
Derivative, Notional Amount [Roll Forward]
Beginning balance	20,000	$ 85,000
Additions	0
Commencements	(20,000)	(65,000)
Maturities	0	0
Ending balance	$ 0	$ 20,000

EARNINGS PER SHARE (Detail) - USD ($) $ in Thousands		12 Months Ended
EARNINGS PER SHARE (Detail) - USD ($) $ in Thousands	Jun. 16, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Net income		$ 25,399	$ 53,079	$ 41,100
Denominator:
Unvested restricted stock awards (in shares)		0	(1,000)	(2,000)
Effect of weighted average shares outstanding (in shares)		(2,821,000)	(68,000)	(97,000)
Basic weighted average shares outstanding		55,174,000	51,623,000	51,312,000
Dilutive effect of stock options and stock awards (in shares)		100,000	144,000	203,000
Diluted weighted average shares outstanding		55,274,000	51,767,000	51,515,000
Antidilutive potentially issuable shares (in shares)		93,000	111,000	10,000
Class A Common Stock
Denominator:
Common stock, outstanding shares		57,007,000	50,704,000	50,423,000
Sale of stock, number of shares issued	6,053,000	6,053
Class B Common Stock
Denominator:
Common stock, outstanding shares		988,000	988,000	988,000

SEGMENT REPORTING

12 Months Ended

Dec. 31, 2023

Segment Reporting [Abstract]

SEGMENT REPORTING

Fiscal Year Ended December 31, 2023


Segment	Outside revenues		Inter-company revenue		Depreciation and amortization		Operating income (loss)		Interest expense, net		Capital expenditures		Goodwill		Total assets
Eastern	$	374,463	$	92,938	$	50,881	$	27,198	$	638	$	43,817	$	73,893	$	434,323
Western	511,640		173,044		82,291		62,318		380		82,706		285,056		1,001,090
Mid-Atlantic (1)	85,640		417		20,263		(5,790)		—		5,271		332,247		553,339
Resource Solutions	292,799		15,337		14,202		5,639		143		14,586		44,474		253,090
Corporate Entities	—		—		3,068		(8,938)		35,676		8,527		—		293,628
Eliminations	—		(281,736)		—		—		—		—		—		—
	$	1,264,542	$	—	$	170,705	$	80,427	$	36,837	$	154,907	$	735,670	$	2,535,470

(1)Operations under the Mid-Atlantic region commenced July 1, 2023.

Fiscal Year Ended December 31, 2022


Segment	Outside revenues		Inter-company revenue		Depreciation and amortization		Operating income (loss)		Interest expense, net		Capital expenditures		Goodwill		Total assets
Eastern	$	340,058	$	83,201	$	47,673	$	16,559	$	565	$	38,501	$	52,406	$	372,895
Western	445,153		151,016		64,116		65,453		508		65,190		183,286		737,658
Mid-Atlantic (1)	—		—		—		—		—		—		—		—
Resource Solutions	299,878		5,734		12,082		15,862		146		15,172		38,766		191,118
Corporate Entities	—		—		2,480		(2,480)		21,794		12,097		—		147,544
Eliminations	—		(239,951)		—		—		—		—		—		—
	$	1,085,089	$	—	$	126,351	$	95,394	$	23,013	$	130,960	$	274,458	$	1,449,215

(1)Operations under the Mid-Atlantic region commenced July 1, 2023.

Fiscal Year Ended December 31, 2021


Segment	Outside revenues		Inter-company revenue		Depreciation and amortization		Operating income (loss)		Interest expense, net		Capital expenditures		Goodwill		Total assets
Eastern	$	264,569	$	66,126	$	33,572	$	12,937	$	456	$	31,489	$	52,072	$	357,446
Western	389,520		132,914		61,055		49,035		159		72,892		163,728		688,826
Mid-Atlantic (1)	—		—		—		—		—		—		—		—
Resource Solutions	235,122		3,258		7,060		17,591		168		12,094		17,060		127,304
Corporate Entities	—		—		1,903		(1,903)		20,144		6,820		—		110,004
Eliminations	—		(202,298)		—		—		—		—		—		—
	$	889,211	$	—	$	103,590	$	77,660	$	20,927	$	123,295	$	232,860	$	1,283,580

(1)Operations under the Mid-Atlantic region commenced July 1, 2023.

Amount of our total revenue attributable to services provided are as follows:


	Fiscal Year Ended December 31,
	2023				2022				2021
Collection	$	710,590	56.2	%	$	539,587	49.7	%	$	442,685	49.8	%
Disposal	244,582		19.3	%	227,971		21.0	%	196,985		22.2	%
Power generation	6,617		0.5	%	7,519		0.7	%	5,138		0.6	%
Processing	9,954		0.8	%	10,134		1.0	%	9,281		1.0	%
Solid waste operations	971,743		76.8	%	785,211		72.4	%	654,089		73.6	%
Processing	105,997		8.4	%	119,045		10.9	%	93,323		10.5	%
National Accounts	186,802		14.8	%	180,833		16.7	%	141,799		15.9	%
Resource Solutions operations	292,799		23.2	%	299,878		27.6	%	235,122		26.4	%
Total revenues	$	1,264,542	100.0	%	$	1,085,089	100.0	%	$	889,211	100.0	%

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-15

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-42

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 40
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-40

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//280/tableOfContent

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 26
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-26

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 34
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-34

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-41

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-21

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-21

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

+ Details

ACCOUNTS RECEIVABLE, NET OF ALLOWANCE FOR CREDIT LOSSES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 3,016	$ 3,276	$ 2,333
Additions - charged to expense	2,468	1,893	1,896
Deductions - write offs charged against the allowance, net of recoveries	(1,418)	(2,153)	(953)
Balance at end of period	$ 4,066	$ 3,016	$ 3,276

COMMITMENTS AND CONTINGENCIES - Reconciliation of Undiscounted Liability to Amount Recognized in Statements of Financial Position (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Undiscounted liability	$ 6,434
Less discount, net	(545)
Liability balance	$ 5,889	$ 6,335	$ 5,887
Environmental loss contingency, statement of financial position, not disclosed	consolidated balance sheet

COMMITMENTS AND CONTINGENCIES - Schedule of Environmental Liability (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 6,335	$ 5,887
Obligations settled	(546)	(415)
Ending balance	5,889	6,335
Less: current portion	1,662	814
Long-term portion	$ 4,227	$ 5,521
Environmental loss contingency, current, statement of financial position, not disclosed	Less: current portion	Less: current portion
Environmental loss contingency, noncurrent, statement of financial position, not disclosed	Long-term portion	Long-term portion
Other environmental remediation sites
Accrual for Environmental Loss Contingencies [Roll Forward]
Accretion expense and obligations incurred	$ 100	$ 104
Inactive waste disposal site
Accrual for Environmental Loss Contingencies [Roll Forward]
Accretion expense and obligations incurred	$ 0	$ 759

STOCKHOLDERS' EQUITY - Summary of Restricted Stock, Restricted Stock Unit and Performance Stock Unit Activity (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares shares
Restricted Stock Awards, Restricted Stock Units and Performance Stock Units
Restricted Stock, Restricted Stock Units, and Performance Stock Units
Outstanding, beginning balance (in shares)	169,000
Granted (in shares)	121,000
Vested (in shares)	(101,000)
Forfeited or canceled (in shares)	(8,000)
Outstanding, ending balance (in shares)	181,000
Unvested, ending balance (in shares)	288,000
Weighted Average Grant Price
Outstanding, beginning balance (in dollars per share) \| $ / shares	$ 75.52
Granted (in dollars per share) \| $ / shares	80.99
Vested (in dollars per share) \| $ / shares	65.21
Forfeited or canceled (in dollars per share) \| $ / shares	77.77
Outstanding, ending balance (in dollars per share) \| $ / shares	84.82
Weighted average grant price, unvested, ending balance (in dollars per share) \| $ / shares	$ 87.35
Weighted average remaining contractual term, outstanding	2 years
Weighted average remaining contractual term, unvested	1 year 10 months 24 days
Aggregate intrinsic value, outstanding \| $	$ 15,474
Aggregate intrinsic value, unvested \| $	$ 24,593
Performance Stock Units
Weighted Average Grant Price
Attainment level percentage	100.00%
Class A Common Stock \| Performance Stock Units
Weighted Average Grant Price
Additional issuance if performance targets met (in shares)	107,000
Additional shares issued	43,000

ACCOUNTING CHANGES (Tables)

12 Months Ended

Dec. 31, 2023

Accounting Changes and Error Corrections [Abstract]

Schedule of Recent Accounting Pronouncements

Standard

Description

Effect on the Financial Statements or Other
Significant Matters

ASU No. 2020-04: Reference Rate Reform (Topic 848), as amended through December 2022

Standard

Description

Effect on the Financial Statements or Other
Significant Matters

Accounting standards issued pending adoption as of December 31, 2023

ASU No. 2023-07: Improvements to Reportable Segment Disclosures (Topic 280)

ASU No. 2023-09: Improvements to Income Tax Disclosures (Topic 740)

EARNINGS PER SHARE

12 Months Ended

Dec. 31, 2023

Earnings Per Share [Abstract]

EARNINGS PER SHARE

A summary of the numerator and denominators used in the computation of earnings per share is as follows:


	Fiscal Year Ended December 31,
	2023		2022		2021
Numerator:
Net income	$	25,399	$	53,079	$	41,100
Denominator:
Class A common stock	57,007		50,704		50,423
Class B common stock	988		988		988

Unvested restricted stock awards	—		(1)		(2)
Effect of weighted average shares outstanding (1)	(2,821)		(68)		(97)
Basic weighted average common shares outstanding	55,174		51,623		51,312
Impact of potentially dilutive securities:
Dilutive effect of stock options and stock awards	100		144		203
Diluted weighted average common shares outstanding	55,274		51,767		51,515
Anti-dilutive potentially issuable shares	93		111		10

STOCKHOLDERS' EQUITY

12 Months Ended

Dec. 31, 2023

Equity [Abstract]

STOCKHOLDERS' EQUITY

Public Offering of Class A Common Stock

On June 16, 2023, we completed a public offering of 6,053 shares of our Class A common stock at a public offering price of $85.50 per share. After deducting stock issuance costs, including underwriting discounts, commissions and offering expenses, the offering resulted in net proceeds of $496,231. The net proceeds from this offering were and are to be used to fund acquisition activity, including the GFL Acquisition and the Twin Bridges Acquisition, to pay certain costs associated with acquisition activities, as discussed in Note 18, Other Items and Charges, and to repay borrowings and/or debt securities as discussed Note 12, Debt.

Common Stock

The holders of the Class A common stock are entitled to one vote for each share held. The holders of the Class B common stock are entitled to ten votes for each share held, except for the election of one director, who is elected by the holders of the Class A common stock exclusively. The Class B common stock is convertible into Class A common stock on a share-for-share basis at the option of the shareholder.

Preferred Stock

We are authorized to issue up to 944 shares of preferred stock in one or more series. As of December 31, 2023 and December 31, 2022, we had no shares issued.

Stock Based Compensation

Stock Incentive Plans

2016 Incentive Plan. In the fiscal year ended December 31, 2016, we adopted the 2016 Incentive Plan (“2016 Plan”). Under the 2016 Plan, we may grant awards up to an aggregate amount of shares equal to the sum of: (i) 2,250 shares of Class A common stock (subject to adjustment in the event of stock splits and other similar events), plus (ii) such additional number of shares of Class A common stock (up to 2,723 shares) as is equal to the sum of the number of shares of Class A common stock that remained available for grant under the 2006 Stock Incentive Plan ("2006 Plan") immediately prior to the expiration of the 2006 Plan and the number of shares of Class A common stock subject to awards granted under the 2006 Plan that expire or otherwise result in shares not being issued.

As of December 31, 2023, there were 616 Class A common stock equivalents available for future grant under the 2016 Plan, inclusive of additional Class A common stock equivalents that were previously issued under terminated plans and have become available for grant because such awards expired or otherwise resulted in shares not being issued.

Our equity awards granted primarily consist of stock options, restricted stock awards, restricted stock units and market-based performance stock units.

Stock options are granted at a price equal to the prevailing fair value of our Class A common stock at the date of grant. Generally, stock options granted have a term not to exceed ten years and vest over a one year to five-year period from the date of grant.

The fair value of each stock option granted is estimated using a Black-Scholes option-pricing model, which uses a risk-free interest rate, based on the U.S. Treasury yield curve for the period of the expected life of the stock option; and requires extensive use of accounting judgment and financial estimation, including estimates of: the expected term, calculated based on the weighted average historical life of the vested stock options, giving consideration to vesting schedules and historical exercise patterns; and the expected volatility, calculated using the weekly historical volatility of our Class A common stock over the expected life of the stock option.

Restricted stock awards and restricted stock units are granted at a price equal to the fair value of our Class A common stock at the date of grant. The fair value of each market-based performance stock unit is estimated using a Monte Carlo pricing model, which requires extensive use of accounting judgment and financial estimation, including the estimated share price appreciation plus the value of dividends of our Class A common stock as compared to the Russell 2000 Index over the requisite service period.

Restricted stock awards granted to non-employee directors vest incrementally over a three-year period beginning on the first anniversary of the date of grant. Restricted stock units granted to non-employee directors vest in full on the first anniversary of the grant date. Restricted stock units vest incrementally over an identified service period beginning on the grant date based on continued employment. Market-based performance stock units vest at a future date following the grant date and are based on the attainment of performance targets and market achievements.

Stock Options

A summary of stock option activity is as follows:


	Stock Options	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value
Outstanding, December 31, 2022	129	$	55.60
Granted	18	$	79.72
Exercised	(18)	$	4.88
Forfeited or expired	—	$	—

Outstanding, December 31, 2023	129	$	66.03	7.5	$	2,504
Exercisable, December 31, 2023	49	$	40.60	5.2	$	2,177

During fiscal years 2023, 2022 and 2021, stock-based compensation expense for stock options was $516, $248 and $28, respectively.

During fiscal years 2023, 2022 and 2021, the aggregate intrinsic value of stock options exercised was $1,302, $1,467 and $1,238, respectively.

As of December 31, 2023, we had $2,108 of unrecognized stock-based compensation expense related to outstanding stock options to be recognized over a weighted average period of 3.9 years.

The fair value of stock options granted in fiscal year 2023 were calculated assuming no expected dividend yield using a weighted average expected life of 5.6 years, a risk-free interest rate of 4.6%, and an expected volatility of 30.0%.

The Black-Scholes valuation model requires extensive use of accounting judgment and financial estimation. Application of alternative assumptions could produce significantly different estimates of the fair value of stock-based compensation and consequently, the related amounts recognized in the consolidated statements of operations.

Other Stock Awards

A summary of restricted stock award, restricted stock unit and performance stock unit activity is as follows:


	Restricted Stock Awards, Restricted Stock Units, and Performance Stock Units (1)	Weighted Average Grant Price		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value
Outstanding, December 31, 2022	169	$	75.52
Granted	121	$	80.99
Class A common stock vested	(101)	$	65.21
Forfeited or canceled	(8)	$	77.77
Outstanding, December 31, 2023	181	$	84.82	2.0	$	15,474
Unvested, December 31, 2023	288	$	87.35	1.9	$	24,593

(1)Performance stock unit grants are included at 100%. Attainment of maximum performance targets and market achievements would result in the issuance of an additional 107 shares of Class A common stock currently included in unvested. The market-based performance stock unit grants that vested in fiscal year 2023 resulted in the issuance of 43 additional shares of Class A common stock.

During fiscal years 2023, 2022 and 2021, stock-based compensation expense related to restricted stock awards, restricted stock units and performance stock units was $8,116, $7,530 and $11,241, respectively.

During fiscal years 2023, 2022 and 2021, the total fair value of other stock awards vested was $12,048, $17,011 and $20,106, respectively.

As of December 31, 2023, total unrecognized stock-based compensation expense related to outstanding restricted stock awards was $8, which will be recognized over a weighted average period of 0.5 years. As of December 31, 2023, total unrecognized stock-based compensation expense related to outstanding restricted stock units was $5,362, which will be recognized over a weighted average period of 2.3 years. As of December 31, 2023, total unrecognized stock-based compensation expense related to performance stock units based on our estimated achievement of the established performance criteria was $4,377, which will be recognized over a weighted average period of 1.6 years.

The weighted average fair value of market-based performance stock units granted during fiscal year 2023 was $83.16 per award, which was calculated using a Monte Carlo pricing model assuming a risk-free interest rate of 4.3% and an expected volatility of 34.9% assuming no expected dividend yield. Risk-free interest rate is based on the U.S. Treasury yield curve for the expected service period of the award. Expected volatility is calculated using the daily volatility of our Class A common stock over the expected service period of the award.

The Monte Carlo pricing model requires extensive use of accounting judgment and financial estimation. Application of alternative assumptions could produce significantly different estimates of the fair value of stock-based compensation and consequently, the related amounts recognized in the consolidated statements of operations.

We also recorded $451, $376 and $281 of stock-based compensation expense related to our Second Amended and Restated Employee Stock Purchase Plan (“ESPP”) during fiscal years 2023, 2022 and 2021, respectively.

Tax benefit for income taxes associated with stock-based compensation during fiscal years 2023, 2022 and 2021 was $(2,330), $(1,744) and $(2,304), respectively.

Accumulated Other Comprehensive (Loss) Income, Net of Tax

Accumulated other comprehensive (loss) income, net of tax is a component of stockholders' equity included in the accompanying consolidated balance sheets and includes, as applicable, the effective portion of changes in the fair value of our cash flow hedges and the changes in fair value of our marketable securities.

The changes in the balances of each component of accumulated other comprehensive (loss) income, net of tax are as follows:


	Interest Rate Swaps
Balance as of December 31, 2020	$	(11,517)

Other comprehensive income before reclassifications	3,737
Amounts reclassified from accumulated other comprehensive loss	4,763
Income tax provision related to items in other comprehensive income	(2,086)
Other comprehensive income	6,414
Balance as of December 31, 2021	(5,103)

Other comprehensive income before reclassifications	15,297
Amounts reclassified from accumulated other comprehensive loss	1,443
Income tax provision related to items in other comprehensive income	(4,095)
Other comprehensive income	12,645
Balance as of December 31, 2022	7,542

Other comprehensive loss before reclassifications	(6,843)
Amounts reclassified from accumulated other comprehensive loss	(6,361)
Income tax benefit related to items in other comprehensive loss	4,582
Other comprehensive loss	(8,622)
Balance as of December 31, 2023	$	(1,080)

A summary of reclassifications out of accumulated other comprehensive (loss) income, net of tax for fiscal years 2023, 2022 and 2021 is as follows:


	Fiscal Year Ended December 31,
	2023		2022		2021
Details About Accumulated Other Comprehensive (Loss) Income, Net of Tax Components	Accumulated Other Comprehensive (Loss) Income, Net of Tax						Affected Line Item in the Consolidated Statements of Operations
Interest rate swaps	$	(6,361)	$	1,443	$	4,763	Interest expense
	6,361		(1,443)		(4,763)		Income before income taxes
	2,633		98		(1,142)		Provision for income taxes
	$	3,728	$	(1,541)	$	(3,621)	Net income

INCOME TAXES - Schedule of Reconciliation of Gross Unrecognized Tax Benefits (Detail)	Dec. 31, 2023 USD ($)
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits at beginning of period	$ 0
Unrecognized tax benefits at end of period	$ 0

DEBT - Schedule of Future Maturities of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Disclosure [Abstract]
Fiscal year ending December 31, 2024	$ 35,781
Fiscal year ending December 31, 2025	66,455
Fiscal year ending December 31, 2026	724,288
Fiscal year ending December 31, 2027	6,965
Fiscal year ending December 31, 2028	6,566
Thereafter	214,491
Principal amount of debt	$ 1,054,546	$ 603,477

EMPLOYEE BENEFIT PLANS (Detail) - USD ($) shares in Thousands		12 Months Ended
	Jun. 01, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2019
Employee Stock Purchase Plan [Line Items]
Employer contributions vesting period		2 years
Employer contributions		$ 4,371,000	$ 3,558,000	$ 2,811,000
Contingent liability term					17 years
Multiemployer pension plan withdrawal obligation, undiscounted					$ 4,224,000
Estimated accumulated benefit obligation as complete withdrawal					$ 18,511,000
Multiemployer pension plan withdrawal obligation		1,496,000
Pension Plan
Employee Stock Purchase Plan [Line Items]
Contributions by employer		$ 479,000	$ 442,000	$ 398,000
Hourly employees \| First matching contribution
Employee Stock Purchase Plan [Line Items]
Employer matching contribution, percent of match		100.00%
Employer matching contribution, percent of employees' annual income		1.00%
Hourly employees \| Next matching contribution
Employee Stock Purchase Plan [Line Items]
Employer matching contribution, percent of match		50.00%
Employer matching contribution, percent of employees' annual income		3.00%
Salary employees
Employee Stock Purchase Plan [Line Items]
Employer matching contribution, percent of match		50.00%
Employer matching contribution, percent of employees' annual income		2.00%
Maximum annual contributions per employee		$ 1,500
Class A Common Stock
Employee Stock Purchase Plan [Line Items]
Discount rate		15.00%
Common stock, additional authorized shares	400
Stock issued under stock purchase plan (in shares)		24	22	20
Stock available for distribution under stock purchase plan (in shares)		407

COMMITMENTS AND CONTINGENCIES - Narrative (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Other Commitments [Line Items]
Loss contingency accrual	$ 6,275
Minimum
Other Commitments [Line Items]
Risk free interest rate	1.50%
Maximum
Other Commitments [Line Items]
Risk free interest rate		7.10%

EMPLOYEE BENEFIT PLANS	12 Months Ended
EMPLOYEE BENEFIT PLANS	Dec. 31, 2023
Retirement Benefits [Abstract]
EMPLOYEE BENEFIT PLANS	EMPLOYEE BENEFIT PLANS Defined Contribution Plan We offer our eligible employees the opportunity to contribute to a 401(k) plan. Under the provisions of the 401(k) plans participants may direct us to defer a portion of their compensation to a 401(k) plan, subject to Internal Revenue Code limitations. In fiscal year 2023, we provided an employer matching contribution for hourly employees equal to 100% of every dollar an employee invests up to 1% of annual income and 50% of additional employee contributions up to a maximum contribution into a 401(k) plan of 3% of annual income. In fiscal year 2023, we provided an employer matching contribution for salaried employees equal to 50% of every dollar an employee invests in a 401(k) plan up to a maximum contribution of one thousand five hundred dollars or up to 2% of annual income, whichever is greater, per employee per calendar year. Participants vest in employer contributions ratable over a two-year period. Employer contributions for fiscal years 2023, 2022 and 2021 amounted to $4,371, $3,558 and $2,811, respectively. Employee Stock Purchase Plan We offer our eligible employees the opportunity to participate in an employee stock purchase plan. Under this plan, qualified employees may purchase shares of Class A common stock by payroll deduction at a 15% discount from the market price. On June 1, 2023, our stockholders approved an amendment and restatement of our employee stock purchase plan to increase the number of shares of Class A common stock reserved for issuance under the employee stock purchase plan by 400 shares of Class A common stock. Class A common stock issued under our ESPP during fiscal years 2023, 2022 and 2021 amounted to 24, 22 and 20 shares, respectively. As of December 31, 2023, 407 shares of Class A common stock were available for distribution under our ESPP. Defined Benefit Pension Plan We contribute to a multiemployer defined benefit pension plan. The Pension Plan, under the terms of a collective bargaining agreement covers certain of our union represented employees. In fiscal year 2019, we reached an agreement to withdraw from the Pension Plan by entering into Withdrawal and Re-entry Agreements with the Pension Plan. The withdrawal generated a fixed yearly contingent liability for us for a period of approximately seventeen (17) years, that capped our gross payments at $4,224, significantly reducing our cash exposure from the potential $18,511 withdrawal liability as determined based on a complete withdrawal prior to withdrawing from the Pension Plan. As of December 31, 2023, we had a remaining obligation of $1,496 in aggregate principal amount associated with our withdrawal. Upon re-entry as a new employer in the Pension Plan, our contributions are projected to fully fund the defined benefits accrued by our employees in the Pension Plan, thereby eliminating future accruals of withdrawal liability. As of December 31, 2023, our employees were fully funded, subject to the terms of the Withdrawal and Re-entry Agreements. Subsequent withdrawal from the Pension Plan, under certain circumstances, may result in a change in the payment schedule required to settle the remaining obligation associated with our withdrawal. During fiscal years 2023, 2022 and 2021, we made contributions to the Pension Plan of $479, $442 and $398, respectively.

- Definition

The entire disclosure for retirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
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-Name Accounting Standards Codification
-Section 50
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Reference 2: http://www.xbrl.org/2003/role/exampleRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480266/715-60-50-3

+ Details

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 25,399	$ 53,079	$ 41,100
Hedging activity:
Interest rate swap settlements	6,259	(1,662)	(4,743)
Interest rate swap amounts reclassified into interest expense	(6,361)	1,443	4,763
Unrealized (loss) gain resulting from changes in fair value of derivative instruments	(13,102)	16,959	8,480
Other comprehensive (loss) income	(13,204)	16,740	8,500
Tax effect related to items of other comprehensive (loss) income	(4,582)	4,095	2,086
Other comprehensive (loss) income, net of tax	(8,622)	12,645	6,414
Comprehensive income	$ 16,777	$ 65,724	$ 47,514

GOODWILL AND INTANGIBLE ASSETS - Components of Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 347,469	$ 166,785
Less accumulated amortization	(106,040)	(75,002)
Intangible assets, net	241,429	91,783
Intangible amortization expenses	31,037	16,593	$ 10,953
Covenants Not-to-Compete
Finite-Lived Intangible Assets [Line Items]
Intangible assets	62,173	31,201
Less accumulated amortization	(26,645)	(24,129)
Intangible assets, net	35,528	7,072
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets	272,571	127,179
Less accumulated amortization	(72,227)	(46,162)
Intangible assets, net	200,344	81,017
Trade Names
Finite-Lived Intangible Assets [Line Items]
Intangible assets	12,725	8,405
Less accumulated amortization	(7,168)	(4,711)
Intangible assets, net	$ 5,557	$ 3,694

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
CURRENT ASSETS:
Cash and cash equivalents	$ 220,912	$ 71,152
Accounts receivable, net of allowance for credit losses of $4,066 and $3,016, respectively	157,324	100,886
Refundable income taxes	3,089	0
Prepaid expenses	17,223	15,182
Inventory	17,859	13,472
Other current assets	9,918	6,787
Total current assets	426,325	207,479
Property and equipment, net of accumulated depreciation and amortization of $1,167,541 and $1,064,756, respectively	980,553	720,550
Operating lease right-of-use assets	100,844	92,063
Goodwill	735,670	274,458
Intangible assets, net	241,429	91,783
Restricted assets	2,203	1,900
Cost method investments	10,967	10,967
Deferred income taxes	11,224	22,903
Other non-current assets	26,255	27,112
Total assets	2,535,470	1,449,215
CURRENT LIABILITIES:
Current maturities of debt	35,781	8,968
Current operating lease liabilities	9,039	7,000
Accounts payable	116,794	74,203
Accrued payroll and related expenses	22,657	23,556
Accrued interest	3,886	2,858
Contract liabilities	31,472	3,742
Current accrued capping, closure and post-closure costs	10,773	11,036
Other accrued liabilities	48,456	46,237
Total current liabilities	278,858	177,600
Debt, less current portion	1,007,662	585,015
Operating lease liabilities, less current portion	66,074	57,345
Accrued capping, closure and post-closure costs, less current portion	123,131	102,642
Deferred income taxes	627	437
Other long-term liabilities	37,327	28,276
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY:
Additional paid-in capital	1,168,812	661,761
Accumulated deficit	(146,521)	(171,920)
Accumulated other comprehensive (loss) income, net of tax	(1,080)	7,542
Total stockholders' equity	1,021,791	497,900
Total liabilities and stockholders' equity	2,535,470	1,449,215
Class A Common Stock
STOCKHOLDERS' EQUITY:
Common stock	570	507
Class B Common Stock
STOCKHOLDERS' EQUITY:
Common stock	$ 10	$ 10

OTHER ACCRUED LIABILITIES

12 Months Ended

Dec. 31, 2023

Payables and Accruals [Abstract]

OTHER ACCRUED LIABILITIES

Other accrued liabilities, classified as current liabilities, at December 31, 2023 and 2022 are as follows:


	December 31,
	2023		2022
Accrued capital expenditures	$	7,362	$	10,842
Other accrued liabilities	41,094		35,395
Total	$	48,456	$	46,237

STOCKHOLDERS' EQUITY - Reclassification Out of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ 47,578	$ 23,722	$ 21,229
Income before income taxes	37,045	74,966	58,046
Provision for income taxes	11,646	21,887	16,946
Net income	25,399	53,079	41,100
Accumulated income (loss), net, cash flow hedge \| Reclassification out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	6,361	(1,443)	(4,763)
Provision for income taxes	2,633	98	(1,142)
Net income	3,728	(1,541)	(3,621)
Accumulated income (loss), net, cash flow hedge \| Interest rate swaps \| Reclassification out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (6,361)	$ 1,443	$ 4,763

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(11))
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/exampleRef
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+ Details

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

- Definition

Amount of the cost of borrowed funds accounted for as interest expense.

+ References + Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

SEGMENT REPORTING - Narrative (Details)	12 Months Ended
SEGMENT REPORTING - Narrative (Details)	Dec. 31, 2023 segment
Solid waste operations
Segment Reporting Information [Line Items]
Operating segments	3

PROPERTY AND EQUIPMENT

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

PROPERTY AND EQUIPMENT

A summary of property and equipment is as follows:


	December 31,
	2023		2022
Land	$	47,863	$	37,321
Landfills	786,130		730,914
Finance lease right-of-use assets	101,770		90,362
Buildings and improvements	262,204		209,234
Machinery and equipment	287,175		243,359
Rolling stock	396,247		276,282
Containers	266,705		197,834
Total property and equipment (1)	2,148,094		1,785,306
Less: accumulated depreciation and amortization	(1,167,541)		(1,064,756)
Property and equipment, net	$	980,553	$	720,550

(1)Includes construction-in-process of $74,408 and $53,439 at December 31, 2023 and December 31, 2022, respectively, that have have not been placed in service and, therefore, have not begun depreciating..

Depreciation expense for fiscal years 2023, 2022 and 2021 was $99,249, $78,139 and $62,342, respectively. Landfill amortization expense for fiscal years 2023, 2022 and 2021 was $40,419, $31,619 and $30,295, respectively.

AUDIT INFORMATION	12 Months Ended
AUDIT INFORMATION	Dec. 31, 2023
Audit Information [Abstract]
Auditor name	RSM US LLP
Auditor location	Boston, Massachusetts
Auditor firm ID	49

FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 113,678	$ 86,914
Obligations incurred	5,447	4,857
Revisions in estimates	14,030	18,415
Accretion expense	9,529	7,565
Obligations settled	(11,801)	(4,073)
Write-off of capping payments	3,021	0
Ending balance	133,904	113,678	$ 86,914
Landfill capping charge - veneer failure	$ 3,021	$ 0	$ 0

SEGMENT REPORTING (Tables)

12 Months Ended

Dec. 31, 2023

Segment Reporting [Abstract]

Schedule of Financial Information by Reportable Segment

Fiscal Year Ended December 31, 2023


Segment	Outside revenues		Inter-company revenue		Depreciation and amortization		Operating income (loss)		Interest expense, net		Capital expenditures		Goodwill		Total assets
Eastern	$	374,463	$	92,938	$	50,881	$	27,198	$	638	$	43,817	$	73,893	$	434,323
Western	511,640		173,044		82,291		62,318		380		82,706		285,056		1,001,090
Mid-Atlantic (1)	85,640		417		20,263		(5,790)		—		5,271		332,247		553,339
Resource Solutions	292,799		15,337		14,202		5,639		143		14,586		44,474		253,090
Corporate Entities	—		—		3,068		(8,938)		35,676		8,527		—		293,628
Eliminations	—		(281,736)		—		—		—		—		—		—
	$	1,264,542	$	—	$	170,705	$	80,427	$	36,837	$	154,907	$	735,670	$	2,535,470

(1)Operations under the Mid-Atlantic region commenced July 1, 2023.

Fiscal Year Ended December 31, 2022


Segment	Outside revenues		Inter-company revenue		Depreciation and amortization		Operating income (loss)		Interest expense, net		Capital expenditures		Goodwill		Total assets
Eastern	$	340,058	$	83,201	$	47,673	$	16,559	$	565	$	38,501	$	52,406	$	372,895
Western	445,153		151,016		64,116		65,453		508		65,190		183,286		737,658
Mid-Atlantic (1)	—		—		—		—		—		—		—		—
Resource Solutions	299,878		5,734		12,082		15,862		146		15,172		38,766		191,118
Corporate Entities	—		—		2,480		(2,480)		21,794		12,097		—		147,544
Eliminations	—		(239,951)		—		—		—		—		—		—
	$	1,085,089	$	—	$	126,351	$	95,394	$	23,013	$	130,960	$	274,458	$	1,449,215

(1)Operations under the Mid-Atlantic region commenced July 1, 2023.

Fiscal Year Ended December 31, 2021


Segment	Outside revenues		Inter-company revenue		Depreciation and amortization		Operating income (loss)		Interest expense, net		Capital expenditures		Goodwill		Total assets
Eastern	$	264,569	$	66,126	$	33,572	$	12,937	$	456	$	31,489	$	52,072	$	357,446
Western	389,520		132,914		61,055		49,035		159		72,892		163,728		688,826
Mid-Atlantic (1)	—		—		—		—		—		—		—		—
Resource Solutions	235,122		3,258		7,060		17,591		168		12,094		17,060		127,304
Corporate Entities	—		—		1,903		(1,903)		20,144		6,820		—		110,004
Eliminations	—		(202,298)		—		—		—		—		—		—
	$	889,211	$	—	$	103,590	$	77,660	$	20,927	$	123,295	$	232,860	$	1,283,580

(1)Operations under the Mid-Atlantic region commenced July 1, 2023.

Schedule of Revenue Attributable to Services Provided by Company

Amount of our total revenue attributable to services provided are as follows:


	Fiscal Year Ended December 31,
	2023				2022				2021
Collection	$	710,590	56.2	%	$	539,587	49.7	%	$	442,685	49.8	%
Disposal	244,582		19.3	%	227,971		21.0	%	196,985		22.2	%
Power generation	6,617		0.5	%	7,519		0.7	%	5,138		0.6	%
Processing	9,954		0.8	%	10,134		1.0	%	9,281		1.0	%
Solid waste operations	971,743		76.8	%	785,211		72.4	%	654,089		73.6	%
Processing	105,997		8.4	%	119,045		10.9	%	93,323		10.5	%
National Accounts	186,802		14.8	%	180,833		16.7	%	141,799		15.9	%
Resource Solutions operations	292,799		23.2	%	299,878		27.6	%	235,122		26.4	%
Total revenues	$	1,264,542	100.0	%	$	1,085,089	100.0	%	$	889,211	100.0	%

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES -Revenue Recognition (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Gross receivables from contracts	$ 158,931	$ 102,234
Contract liabilities	$ 31,472	$ 3,742

DEBT - Components of Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Interest expense on long-term debt and finance leases	$ 44,836	$ 21,691	$ 19,201
Amortization of debt issuance costs	2,962	1,903	2,288
Letter of credit fees	423	458	458
Less: capitalized interest	(643)	(330)	(718)
Total interest expense	47,578	$ 23,722	$ 21,229
GFL Environmental Inc
Debt Instrument [Line Items]
Amortization of debt issuance costs	395
Twin Bridges Acquisition
Debt Instrument [Line Items]
Amortization of debt issuance costs	$ 101

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

- Definition

Amount of the cost of borrowed funds accounted for as interest expense.

+ References + Details

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Schedule of Recurring Fair Value Measurements

Summaries of our financial assets and liabilities that are measured at fair value on a recurring basis are as follows:


	Fair Value Measurement at December 31, 2023 Using:
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:

Interest rate swaps	$	—	$	10,364	$	—
Restricted investment securities - landfill closure	2,203		—		—
	$	2,203	$	10,364	$	—
Liabilities:
Interest rate swaps	$	—	$	11,762	$	—
	$	—	$	11,762	$	—


	Fair Value Measurement at December 31, 2022 Using:
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Interest rate swaps	$	—	$	11,806	$	—

Restricted investment securities - landfill closure	1,900		—		—
	$	1,900	$	11,806	$	—
Liabilities:
Interest rate swaps	$	—	$	—	$	—
Contingent consideration - acquisition (1)	—		—		965
	$	—	$	—	$	965

REVENUE RECOGNITION

12 Months Ended

Dec. 31, 2023

Revenue from Contract with Customer [Abstract]

REVENUE RECOGNITION

We disaggregate our revenues by applicable service line as follows: collection, landfill, transfer, transportation, landfill gas-to-energy, processing and National Accounts.

Collection

Collection revenues are principally generated by providing waste collection and disposal services to our customers. Services may be provided as needed or as scheduled. We derive a substantial portion of our collection revenues from commercial, industrial and municipal services that are generally performed under service agreements or pursuant to contracts with municipalities. The majority of our residential collection services are performed on a subscription basis with individual property owners or occupants.

Landfill

Landfill disposal services primarily consist of receiving some form of acceptable solid waste materials at one of our landfills and appropriately disposing of it. Landfill customers are typically charged a tipping fee on a per ton basis for disposing of their solid waste at our disposal facilities. In general, these fees are variable in nature.

Transfer station

Transfer station disposal services primarily consist of receiving some form of acceptable solid waste materials at one of our transfer stations and appropriately disposing of it by transporting it to an appropriate disposal site. Transfer station customers are charged a tipping fee on a per ton basis for disposing of their solid waste at our transfer stations. In general, these fees are variable in nature.

Transportation

Transportation services consist of the transportation of large volumes of waste or recycled materials from a customer designated location to another location or disposal facility. Transportation customers are charged a fee on a per ton basis for transporting and/or disposal of the materials. In general, these fees are variable in nature.

Landfill gas-to-energy

Landfill gas-to-energy services primarily consist of the generation and sale of electricity from landfill gas-to-energy facilities located at certain of our landfills; the reservation of electric generating capacity to be used by a customer on demand; and the sale of RECs.

Processing

Processing services consist of the receipt of recycled, sludge or other organic materials at one of our materials recovery, processing or disposal facilities, where it is then sorted, mixed and/or processed, and then disposed of or sold. Revenues from processing services are derived from customers in the form of processing fees, tipping fees, and commodity sales, primarily comprised of newspaper, corrugated containers, plastics, ferrous and aluminum, and organic materials such as our earthlife® soils products including fertilizers, composts and mulches.

National Accounts

Revenues from our National Accounts business are derived from brokerage services and overall resource management services providing a wide range of environmental services and resource management solutions to large and complex organizations, as well as traditional collection, disposal and recycling services provided to large account multi-site customers. In brokerage arrangements, we act as an agent that facilitates the sale of recyclable materials between an inbound customer and an outbound customer. Revenues from the brokerage of recycled materials are recognized on a net basis at the time of shipment. In general, these fees are variable in nature.

A table of revenues disaggregated by service line and timing of revenue recognition by operating segment follows:

Fiscal Year Ended December 31, 2023


	Eastern		Western		Mid-Atlantic (1)		Resource Solutions		Total Revenues
Collection	$	266,991	$	358,883	$	84,716	$	—	$	710,590
Landfill	28,275		72,726		—		—		101,001
Transfer	65,401		56,630		924		—		122,955
Transportation	4,994		15,632		—		—		20,626
Landfill gas-to-energy	806		5,811		—		—		6,617
Processing	7,996		1,958		—		105,997		115,951
National Accounts	—		—		—		186,802		186,802
Total revenues	$	374,463	$	511,640	$	85,640	$	292,799	$	1,264,542

Transferred at a point-in-time	$	463	$	2,731	$	—	$	34,654	$	37,848
Transferred over time	374,000		508,909		85,640		258,145		1,226,694
Total revenues	$	374,463	$	511,640	$	85,640	$	292,799	$	1,264,542

(1)Operations under the Mid-Atlantic region commenced July 1, 2023.

Fiscal Year Ended December 31, 2022


	Eastern		Western		Mid-Atlantic (1)		Resource Solutions		Total Revenues
Collection	$	233,043	$	306,544	$	—	$	—	$	539,587
Landfill	27,301		70,241		—		—		97,542
Transfer	65,800		44,762		—		—		110,562
Transportation	5,619		14,248		—		—		19,867
Landfill gas-to-energy	925		6,594		—		—		7,519
Processing	7,370		2,764		—		119,045		129,179
National Accounts	—		—		—		180,833		180,833
Total revenues	$	340,058	$	445,153	$	—	$	299,878	$	1,085,089

Transferred at a point-in-time	$	462	$	2,138	$	—	$	52,735	$	55,335
Transferred over time	339,596		443,015		—		247,143		1,029,754
Total revenues	$	340,058	$	445,153	$	—	$	299,878	$	1,085,089

(1)Operations under the Mid-Atlantic region commenced July 1, 2023.

Fiscal Year Ended December 31, 2021


	Eastern		Western		Mid-Atlantic (1)		Resource Solutions		Total Revenues
Collection	$	175,816	$	266,869	$	—	$	—	$	442,685
Landfill	25,241		66,732		—		—		91,973
Transfer	53,882		37,400		—		—		91,282
Transportation	1,683		12,047		—		—		13,730
Landfill gas-to-energy	1,052		4,086		—		—		5,138
Processing	6,895		2,386		—		93,323		102,604
National Accounts	—		—		—		141,799		141,799
Total revenues	$	264,569	$	389,520	$	—	$	235,122	$	889,211

Transferred at a point-in-time	$	166	$	1,719	$	—	$	63,666	$	65,551
Transferred over time	264,403		387,801		—		171,456		823,660
Total revenues	$	264,569	$	389,520	$	—	$	235,122	$	889,211

(1)Operations under the Mid-Atlantic region commenced July 1, 2023.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-9

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-10

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-15

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-13

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org//606/tableOfContent

+ Details

BASIS OF PRESENTATION	12 Months Ended
BASIS OF PRESENTATION	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION Casella Waste Systems, Inc. (“Parent”) and its subsidiaries (collectively, “we”, “us” or “our”), is a regional, vertically integrated solid waste services company. We provide resource management expertise and services to residential, commercial, municipal, institutional and industrial customers, primarily in the areas of solid waste collection and disposal, transfer, recycling and organics services. We provide integrated solid waste services in nine states: Vermont, New Hampshire, New York, Massachusetts, Connecticut, Maine, Pennsylvania, Delaware and Maryland, with our headquarters located in Rutland, Vermont. On June 30, 2023, we acquired the equity interests of four wholly owned subsidiaries of GFL Environmental Inc. ("GFL Subsidiaries"), which are the basis of our newly formed regional operating segment, the Mid-Atlantic region, that expanded our integrated solid waste services into the states of Delaware and Maryland ("GFL Acquisition"). See Note 5, Business Combinations for further disclosure. Operations under the Mid-Atlantic region commenced on July 1, 2023. The GFL Acquisition was funded from financing transactions (see Note 12, Debt for further disclosure), the net proceeds from an equity offering completed June 16, 2023 (see Note 14, Stockholders’ Equity for further disclosure) and cash on hand. We manage our solid waste operations on a geographic basis through three regional operating segments, the Eastern, Western and Mid-Atlantic regions, each of which provides a comprehensive range of non-hazardous solid waste services. We manage our resource renewal operations through the Resource Solutions operating segment, which leverages our core competencies in materials processing, industrial recycling, organics and resource management service offerings to deliver a comprehensive solution for our larger commercial, municipal, institutional and industrial customers that have more diverse waste and recycling needs. Legal, tax, information technology, human resources, certain finance and accounting and other administrative functions are included in our Corporate Entities segment. The accompanying consolidated financial statements, which include the accounts of the Parent and our wholly-owned subsidiaries have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). All significant intercompany accounts and transactions are eliminated in consolidation. Investments in entities in which we do not have a controlling financial interest are accounted for under either the equity method or the cost method of accounting, as appropriate.

DEBT - Tax-Exempt Financings (Details) - Unsecured Debt - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Aggregate principal amount outstanding	$ 232,000
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2020R-2 ("New York Bonds 2020R-2") due September 2050 - fixed rate interest period bearing interest at 5.125% through September 2030
Debt Instrument [Line Items]
Aggregate principal amount outstanding	35,000	$ 0
Aggregate principal amount issued	35,000
Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2022A-1 ("Vermont Bonds 2022A-1") due June 2052 - fixed rate interest period bearing interest at 5.00% through May 2027
Debt Instrument [Line Items]
Aggregate principal amount outstanding	$ 35,000	35,000
Aggregate principal amount issued		$ 35

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

COMMITMENTS AND CONTINGENCIES

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

In the ordinary course of our business and as a result of the extensive governmental regulation of the solid waste industry, we are subject to various judicial and administrative proceedings involving state and local agencies. In these proceedings, an agency may seek to impose fines or to revoke or deny renewal of an operating permit held by us. From time to time, we may also be subject to actions brought by special interest or other groups, adjacent landowners or residents in connection with the permitting and licensing of landfills and transfer stations, or allegations of environmental damage or violations of the permits and licenses pursuant to which we operate. In addition, we may be named defendants in various claims and suits pending for alleged damages to persons and property, alleged violations of certain laws and alleged liabilities arising out of matters occurring during the ordinary operation of a waste management business. The plaintiffs in some actions seek unspecified damages or injunctive relief, or both. These actions fall within various procedural stages at any point in time, and some are covered in part by insurance.

In accordance with FASB ASC 450 - Contingencies, we accrue for legal proceedings, inclusive of legal costs, when losses become probable and reasonably estimable. We have recorded an aggregate accrual of $6,275 relating to our outstanding legal proceedings as of December 31, 2023. As of the end of each applicable reporting period, we review each of our legal proceedings to determine whether it is probable, reasonably possible or remote that a liability has been incurred and, if it is at least reasonably possible, whether a range of loss can be reasonably estimated under the provisions of FASB ASC 450-20. In instances where we determine that a loss is probable and we can reasonably estimate a range of loss we may incur with respect to such a matter, we record an accrual for the amount within the range that constitutes our best estimate of the possible loss. If we are able to reasonably estimate a range, but no amount within the range appears to be a better estimate than any other, we record an accrual in the amount that is the low end of such range. When a loss is reasonably possible, but not probable, we will not record an accrual, but we will disclose our estimate of the possible range of loss where such estimate can be made in accordance with FASB ASC 450-20. We disclose outstanding matters that we believe could have a material adverse effect on our financial condition, results of operations or cash flows. See Note 18, Other Items and Charges for disclosure regarding a legal settlement charge recorded in fiscal year 2023.

Legal Proceedings

North Country Environmental Services Expansion Permit

The permit for expansion of the Bethlehem, New Hampshire landfill of our subsidiary, North Country Environmental Services, Inc. (“NCES”), known as “Stage VI”, issued in October 2020 (“Permit”), was appealed by the Conservation Law Foundation (“CLF”) to the New Hampshire Waste Management Council (“Council”) on November 9, 2020 on the grounds it failed to meet the public benefit criteria. Following a hearing on the merits during which the Council found that the New Hampshire Department of Environmental Services (“DES”) had reasonably measured and acted lawfully in determining a capacity need for Stage VI, the hearing officer presiding over the proceedings issued an Order on May 11, 2022, without further hearing, determining instead that DES had acted unlawfully in reaching these conclusions (“Hearing Officer’s Order”), and remanded the Permit to DES on this determination. On December 5, 2022, DES and NCES both separately sought review of the Hearing Officer’s Order on appeal to the New Hampshire Supreme Court (“Supreme Court”). The parties presented oral arguments to the Supreme Court on October 3, 2023. On December 28, 2023, the Supreme Court issued a decision reversing the Hearing Officer's Order and held that the Stage VI Permit was lawfully issued by DES, fully resolving this matter and upholding the Stage VI Permit.

On December 14, 2022, NCES filed an action in Merrimack Superior Court (“Superior Court”) seeking to invalidate the Hearing Officer’s Order as having been adopted in violation of New Hampshire’s statute governing access to public records and meetings in that the Council did not hold a public meeting to deliberate on the Hearing Officer’s Order. The Superior Court

dismissed that proceeding by Order dated April 6, 2023, and NCES appealed that decision to the Supreme Court on April 18, 2023. NCES’s brief on appeal was filed with the Supreme Court on August 11, 2023. On September 26, 2023, CLF filed a Motion to Intervene as well as a memorandum of law asking the Supreme Court to uphold the Superior Court’s dismissal, to which NCES filed an Objection in response on October 23, 2023. The Council filed its brief on October 25, 2023. On November 9, 2023, the Supreme Court issued an Order denying CLF’s Motion to Intervene but treating CLF’s memorandum of law as an amicus brief. NCES filed a reply brief on November 14, 2023. On January 18, 2024, the Supreme Court issued an Order setting a deadline of February 2, 2024 for the parties to submit memoranda addressing the mootness of this appeal in light of the Supreme Court’s December 28, 2023 Order reversing the Hearing Officer’s Order and upholding the Stage VI Permit. NCES subsequently filed a Motion for Vacatur of the Superior Court’s April 6, 2023 Order and a Memorandum in Response to the Supreme Court's February 2, 2024 Order on January 23, 2024. A ruling on the Supreme Court's question of mootness and NCES's Motion for Vacatur remains pending.

On September 20, 2022, NCES, which has since withdrawn as a party, and our subsidiary, Granite State Landfill, LLC ("GSL"), filed a Petition for Declaratory Judgment ("Petition") in the Superior Court asking the Superior Court for a determination of the meaning and constitutionality of New Hampshire’s public benefit requirement, the same statute at issue in the Hearing Officer’s Order. CLF was granted intervention in the Petition proceeding on June 8, 2023. On December 19, 2023, GSL filed a Motion To Stay pending the outcome of the Supreme Court’s consideration of the Stage VI Permit appeal. The Stage VI Permit appeal was decided and upheld by Order of December 28, 2023 as discussed above. As NCES prevailed in the Stage VI Permit appeal, GSL and NCES voluntarily non-suited the Petition on January 2, 2024, resolving this matter.

On April 12, 2023, DES issued approval of construction plans for Stage VI, Phase II to NCES (“DES Approval”). CLF appealed the DES Approval to the Council on May 11, 2023, on the grounds that it failed to meet the public benefit criteria, and that the DES Approval conflicts with the Hearing Officer’s May 11, 2022 Order determining that DES had acted unlawfully in issuing the Permit, and requested expedited review. The Council has denied CLF's request for expedited review. CLF withdrew its appeal by notice to the Council on February 7, 2024. In light of CLF's withdrawal of appeal, this matter is fully resolved.

Environmental Remediation Liabilities

We are subject to liability for environmental damage, including personal injury and property damage, that our solid waste, recycling and power generation facilities may cause to neighboring property owners, particularly as a result of the contamination of drinking water sources or soil, possibly including damage resulting from conditions that existed before we acquired the facilities. We may also be subject to liability for similar claims arising from off-site environmental contamination caused by pollutants or hazardous substances if we or our predecessors arrange or arranged to transport, treat or dispose of those materials.

We accrue for costs associated with environmental remediation obligations when such costs become both probable and reasonably estimable. Determining the method and ultimate cost of remediation requires that a number of assumptions be made. There can sometimes be a range of reasonable estimates of the costs associated with remediation of a site. In these cases, we use the amount within the range that constitutes our best estimate. In the early stages of the remediation process, particular components of the overall liability may not be reasonably estimable; in this instance we use the components of the liability that can be reasonably estimated as a surrogate for the liability. It is reasonably possible that we will need to adjust the liabilities recorded for remediation to reflect the effects of new or additional information, to the extent such information impacts the costs, timing or duration of the required actions. Future changes in our estimates of the cost, timing or duration of the required actions could have a material adverse effect on our consolidated financial position, results of operations and cash flows. We disclose outstanding environmental remediation matters that remain unsettled or are settled in the reporting period that we believe could have a material adverse effect on our financial condition, results of operations or cash flows.

We inflate the estimated costs in current dollars to the expected time of payment and discount the total cost to present value using a risk-free interest rate. The risk-free interest rates associated with our environmental remediation liabilities as of December 31, 2023 range between 1.5% and 7.1%. A summary of the changes to the aggregate environmental remediation liabilities for the twelve months ended December 31, 2023 and 2022 follows:


	Twelve Months Ended December 31,
	2023		2022
Beginning balance	$	6,335	$	5,887
Accretion expense	100		104
Obligations incurred (1)	—		759

Obligations settled (2)	(546)		(415)
Ending balance	5,889		6,335
Less: current portion	1,662		814
Long-term portion	$	4,227	$	5,521

(1)Associated with the investigation of potential remediation at an inactive waste disposal site that adjoins one of the landfills that we operate.

(2)May include amounts paid and amounts that are being processed through accounts payable as a part of our disbursement cycle.

The total expected environmental remediation payments, as of December 31, 2023 for each of the next five fiscal years and thereafter are as follows:



Fiscal year ending December 31, 2024	$	1,499
Fiscal year ending December 31, 2025	308
Fiscal year ending December 31, 2026	318
Fiscal year ending December 31, 2027	299
Fiscal year ending December 31, 2028	306
Thereafter	3,704
Total	$	6,434

A reconciliation of the expected aggregate non-inflated, undiscounted environmental remediation liabilities to the amount recognized in our consolidated balance sheet at December 31, 2023 is as follows:



Undiscounted liability	$	6,434
Less discount, net	(545)
Liability balance - December 31, 2023	$	5,889

Any substantial liability incurred by us arising from environmental damage could have a material adverse effect on our business, financial condition and results of operations.

COMMITMENTS AND CONTINGENCIES (Tables)

12 Months Ended

Dec. 31, 2023

Commitments and Contingencies Disclosure [Abstract]

Schedule of Environmental Remedial Liability

A summary of the changes to the aggregate environmental remediation liabilities for the twelve months ended December 31, 2023 and 2022 follows:


	Twelve Months Ended December 31,
	2023		2022
Beginning balance	$	6,335	$	5,887
Accretion expense	100		104
Obligations incurred (1)	—		759

Obligations settled (2)	(546)		(415)
Ending balance	5,889		6,335
Less: current portion	1,662		814
Long-term portion	$	4,227	$	5,521

(1)Associated with the investigation of potential remediation at an inactive waste disposal site that adjoins one of the landfills that we operate.

(2)May include amounts paid and amounts that are being processed through accounts payable as a part of our disbursement cycle.

Schedule of Total Expected Environmental Remediation Payments for Succeeding Year

The total expected environmental remediation payments, as of December 31, 2023 for each of the next five fiscal years and thereafter are as follows:



Fiscal year ending December 31, 2024	$	1,499
Fiscal year ending December 31, 2025	308
Fiscal year ending December 31, 2026	318
Fiscal year ending December 31, 2027	299
Fiscal year ending December 31, 2028	306
Thereafter	3,704
Total	$	6,434

Schedule of Reconciliation of Expected Aggregate Non-inflated, Undiscounted Environmental Remediation Liability to Amount Recognized in Statement of Financial Position



Undiscounted liability	$	6,434
Less discount, net	(545)
Liability balance - December 31, 2023	$	5,889

INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of Benefit for Income Taxes

A summary of the provision for income taxes is as follows:


	Fiscal Year Ended December 31,
	2023		2022		2021
Federal


Deferred	8,155		15,645		12,356
	8,155		15,645		12,356
State
Current	4,385		5,362		1,873

Deferred	(894)		880		2,717
	3,491		6,242		4,590
Provision for income taxes	$	11,646	$	21,887	$	16,946

Schedule of Difference in Benefit for Income Taxes

The differences in the provision for income taxes and the amounts determined by applying the Federal statutory rate to income before income taxes are as follows:


	Fiscal Year Ended December 31,
	2023			2022			2021
Federal statutory rate	21		%	21		%	21		%
Tax at statutory rate	$	7,779		$	15,743		$	12,190
State income taxes, net of federal benefit	1,383			6,087			3,868
Change in valuation allowance	912			(1,425)			(388)
Federal effect of change in state valuation allowance	(312)			282			74
Non-deductible officer compensation	996			1,300			1,338
Non-deductible expenses	809			782			322

Deductible stock awards	(963)			(627)			(363)
Tax credits	(60)			(83)			(153)
Reversal of disproportionate tax effects in other comprehensive (loss) income	938			—			—



Other, net	164			(172)			58
Provision for income taxes	$	11,646		$	21,887		$	16,946

Schedule of Deferred Tax Assets and Liabilities


	December 31,
	2023		2022
Deferred tax assets:
Accrued expenses and reserves	$	49,339	$	43,437
Net operating loss carryforwards	30,165		13,398
General business and state tax credit carryforwards	6,862		6,987
Interest expense limitation	6,690		—
Stock awards	2,690		2,728
Unrealized loss on swaps	375		—



Other	1,567		2,419
Total deferred tax assets	97,688		68,969
Less: valuation allowance	(5,580)		(4,668)
Total deferred tax assets after valuation allowance	92,108		64,301
Deferred tax liabilities:
Tax over book depreciation of property and equipment	(58,927)		(21,561)
Amortization of intangibles	(22,540)		(17,252)
Unrealized gain on swaps	—		(3,022)

Other	(44)		—
Total deferred tax liabilities	(81,511)		(41,835)
Net deferred tax asset	$	10,597	$	22,466

OTHER ACCRUED LIABILITIES (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued capital expenditures	$ 7,362	$ 10,842
Other accrued liabilities	41,094	35,395
Total	$ 48,456	$ 46,237

INCOME TAXES - Schedule of Benefit for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Federal
Deferred	$ 8,155	$ 15,645	$ 12,356
Total	8,155	15,645	12,356
State
Current	4,385	5,362	1,873
Deferred	(894)	880	2,717
Total	3,491	6,242	4,590
Provision for income taxes	$ 11,646	$ 21,887	$ 16,946

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive ( Loss) Income, Net of Tax	Class A Common Stock	Class A Common Stock Common Stock	Class B Common Stock	Class B Common Stock Common Stock
Beginning balance at Dec. 31, 2020	$ 362,142	$ 639,247	$ (266,099)	$ (11,517)		$ 501		$ 10
Beginning balance (in shares) at Dec. 31, 2020						50,101,000		988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	1,250	1,247				$ 3
Issuances of Class A common stock (in shares)						322,000
Stock-based compensation	11,551	11,551
Net income	41,100		41,100
Hedging activity	6,414			6,414
Ending balance at Dec. 31, 2021	422,457	652,045	(224,999)	(5,103)		$ 504		$ 10
Ending balance (in shares) at Dec. 31, 2021					50,423,000	50,423,000	988,000	988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	1,564	1,561				$ 3
Issuances of Class A common stock (in shares)						281,000
Stock-based compensation	8,155	8,155
Net income	53,079		53,079
Hedging activity	12,645			12,645
Ending balance at Dec. 31, 2022	497,900	661,761	(171,920)	7,542		$ 507		$ 10
Ending balance (in shares) at Dec. 31, 2022					50,704,000	50,704,000	988,000	988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A common stock - equity offering, net of stock issuance costs	496,231	496,170				$ 61
Issuance of Class A common stock - equity offering, net of stock issuance costs (in shares)						6,053,000
Issuances of Class A common stock	1,799	1,797				$ 2
Issuances of Class A common stock (in shares)						250,000
Stock-based compensation	9,084	9,084
Net income	25,399		25,399
Hedging activity	(8,622)			(8,622)
Ending balance at Dec. 31, 2023	$ 1,021,791	$ 1,168,812	$ (146,521)	$ (1,080)		$ 570		$ 10
Ending balance (in shares) at Dec. 31, 2023					57,007,000	57,007,000	988,000	988,000

OTHER ITEMS AND CHARGES - Charges Associated with Closure of Southbridge Landfill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Site Contingency [Line Items]
Southbridge Landfill closure charge, net	$ 467	$ 1,436	$ 496
Southbridge Landfill
Site Contingency [Line Items]
Legal and transaction costs	412	684	868
Contract settlement charge	0	0	572
Landfill closure project charge (credit)	55	752	(944)
Southbridge Landfill closure charge, net	$ 467	$ 1,436	$ 496

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References + Details

Insider Trading Arrangements

3 Months Ended

12 Months Ended

Dec. 31, 2023

Trading Arrangements, by Individual

Non-Rule 10b5-1 Arrangement Adopted

false

Rule 10b5-1 Arrangement Terminated

false

Non-Rule 10b5-1 Arrangement Terminated

false

Bradford J. Helgeson [Member]

Trading Arrangements, by Individual

Material Terms of Trading Arrangement

Name (Title)

Action Taken (Date of Action)

Type of Trading Arrangement

Nature of Trading Arrangement

Duration of Trading Arrangement

Aggregate Number of Securities

Bradford J. Helgeson

(Executive Vice president and Chief Financial Officer)

Adoption

(11/16/2023)

Durable Rule 10b5-1 trading arrangement for sell-to-cover transactions relating to certain equity awards that have or may be granted

Sale

Until final settlement of any covered RSU or PSU

Indeterminable(1)

Name

Bradford J. Helgeson

Title

Executive Vice president and Chief Financial Officer

Rule 10b5-1 Arrangement Adopted

true

Adoption Date

11/16/2023

BUSINESS COMBINATIONS - Schedule of Purchase Price Paid for Acquisitions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Purchase Price:
Cash used in acquisitions, net of cash acquired	$ 851,839	$ 78,197	$ 170,647
Open working capital settlements due from sellers	(2,873)	0	0
Allocated as follows:
Excess purchase price to be allocated to goodwill	735,670	274,458	232,860
Transfer Stations Acquisition
Purchase Price:
Cash used in acquisitions, net of cash acquired	846,711	76,573	166,489
Other non-cash consideration	0	1,275	0
Holdbacks, additional consideration owed to sellers and contingent consideration	2,729	4,840	5,194
Total consideration	846,567	82,688	171,683
Allocated as follows:
Current assets	19,524	7,644	7,218
Land	8,440	3,141	1,321
Finance lease right-of-use-assets	0	0	31,467
Buildings and improvements	28,411	8,576	11,046
Machinery, equipment and other	177,916	11,689	46,396
Operating lease right-of-use assets	11,786	405	6,500
Deferred tax liability	(9,058)	0	0
Current liabilities	(21,417)	(3,812)	(6,014)
Other long-term liabilities	(828)	(123)	0
Financing lease liabilities, less current portion	0	0	(10,535)
Operating lease liabilities, less current portion	(9,939)	(282)	0
Fair value of assets acquired and liabilities assumed	385,408	41,981	133,751
Excess purchase price to be allocated to goodwill	461,159	40,707	37,932
Accounts receivable	17,002	6,806	5,340
Transfer Stations Acquisition \| Trade Names
Allocated as follows:
Intangible assets	4,320	55	8,350
Transfer Stations Acquisition \| Covenants Not-to-Compete
Allocated as follows:
Intangible assets	30,860	2,424	1,807
Transfer Stations Acquisition \| Customer Relationships
Allocated as follows:
Intangible assets	145,393	12,224	36,195
Other non-current assets	$ 0	$ 40	$ 0

RELATED PARTY TRANSACTIONS (Detail) $ in Thousands	12 Months Ended
RELATED PARTY TRANSACTIONS (Detail) $ in Thousands	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Apr. 30, 1994 lease
Related Party Transaction [Line Items]
Total services purchased	$ 7,682	$ 12,297	$ 15,206
Current liabilities	278,858	177,600
Revenues	1,264,542	1,085,089	889,211
Number of leases \| lease				2
Amortization of right-of-use assets	7,383	6,339
Accrued costs associated with post-closure obligations	133,904	113,678	86,914
Landfills
Related Party Transaction [Line Items]
Landfill post-closure cost	3	10	12
Accrued costs associated with post-closure obligations	17	17
Related Party
Related Party Transaction [Line Items]
Current liabilities	595	1,891
Revenues	241	141	430
Leases monthly payments	29
Amortization of right-of-use assets	$ 284	$ 273	$ 297

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Defined Benefit Pension Plan (Details)	12 Months Ended
	Dec. 31, 2023 plan
Pension Plan
Multiemployer Plans [Line Items]
Number of plans	1

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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+ Details

DEBT

12 Months Ended

Dec. 31, 2023

Debt Disclosure [Abstract]

DEBT

A summary of debt is as follows:


	December 31,
	2023		2022
Senior Secured Credit Facility:
Term Loan A Facility ("Term Loan Facility") due December 2026; bearing interest at 7.083% as of December 31, 2023	$	350,000	$	350,000
Term Loan A Facility ("2023 Term Loan Facility") due December 2026; bearing interest at 7.581% as of December 31, 2023	419,250		—
Revolving Credit Facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.725%	—		6,000
Tax-Exempt Bonds:
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014 ("New York Bonds 2014R-1") due December 2044 - fixed rate interest period bearing interest at 2.875% through December 2029	25,000		25,000
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014R-2 ("New York Bonds 2014R-2") due December 2044 - fixed rate interest period bearing interest at 3.125% through May 2026	15,000		15,000
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2020 ("New York Bonds 2020") due September 2050 - fixed rate interest period bearing interest at 2.750% through September 2025	40,000		40,000
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2020R-2 ("New York Bonds 2020R-2") due September 2050 - fixed rate interest period bearing interest at 5.125% through September 2030	35,000		—
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2005R-3 ("FAME Bonds 2005R-3") due January 2025 - fixed rate interest period bearing interest at 5.25% through January 2025	25,000		25,000
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-1 ("FAME Bonds 2015R-1") due August 2035 - fixed rate interest period bearing interest at 5.125% through July 2025	15,000		15,000
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-2 ("FAME Bonds 2015R-2") due August 2035 - fixed rate interest period bearing interest at 4.375% through July 2025	15,000		15,000
Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2013 ("Vermont Bonds 2013") due April 2036 - fixed rate interest period bearing interest at 4.625% through April 2028	16,000		16,000
Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2022A-1 ("Vermont Bonds 2022A-1") due June 2052 - fixed rate interest period bearing interest at 5.00% through May 2027	35,000		35,000
Business Finance Authority of the State of New Hampshire Solid Waste Disposal Revenue Bonds Series 2013 ("New Hampshire Bonds") due April 2029 - fixed rate interest period bearing interest at 2.95% through April 2029	11,000		11,000
Other:
Finance leases maturing through December 2107; bearing interest at a weighted average of 4.0%	53,066		49,813
Notes payable maturing through March 2025; bearing interest up to 8.1%	230		664
Principal amount of debt	1,054,546		603,477
Less—unamortized debt issuance costs	11,103		9,494
Debt less unamortized debt issuance costs	1,043,443		593,983
Less—current maturities of debt	35,781		8,968
Debt, less current portion	$	1,007,662	$	585,015

Credit Facility

In February 2023, we entered into first and second amendments to our Amended and Restated Credit Agreement. The first amendment provides, commencing in the fiscal year ending December 31, 2024, that the interest rate margin applied for drawn and undrawn amounts under the Amended and Restated Credit Agreement shall be separately adjusted based on our achievement of certain thresholds and targets on two sustainability related key performance indicator metrics during the prior fiscal year: (i) metric tons of solid waste materials reduced, reused or recycled through our direct operations or with third-parties in collaboration with customers; and (ii) our total recordable incident rate. The second amendment provides that loans under the Amended and Restated Credit Agreement shall bear interest, at our election, at Term SOFR, including a secured overnight financing rate adjustment of 10 basis points, or at a base rate, in each case, plus or minus any sustainable rate adjustment plus an applicable interest rate margin based upon our consolidated net leverage ratio.

In April 2023, we entered into an equity purchase agreement pursuant to which we agreed to the GFL Acquisition. In connection with the GFL Acquisition, we entered into (i) a commitment letter to obtain short-term secured bridge financing of up to $375,000 and (ii) the third amendment to the Amended and Restated Credit Agreement to, among other things, permit the draw down of the short-term secured bridge financing and authorize a delayed draw term loan facility to be executed with customary limited condition provisions. The short-term secured bridge financing was undrawn and subsequently terminated in May 2023 when we entered into a loan joinder, which provided for a $430,000 aggregate principal amount 2023 Term Loan Facility under the Amended and Restated Credit Agreement. In June 2023, we borrowed $430,000 under the 2023 Term Loan Facility and paid certain fees and costs due and payable in connection therewith. Borrowings from the 2023 Term Loan Facility were used to fund, in conjunction with the net proceeds from the public offering of our Class A common stock completed on June 16, 2023, cash and cash equivalents and borrowings from our Revolving Credit Facility, the GFL Acquisition. See Note 14, Stockholders' Equity for further disclosure regarding the public offering.

In June 2023, we entered into an asset purchase agreement pursuant to which we agreed to the Twin Bridges Acquisition. In connection with the Twin Bridges Acquisition, we entered into a commitment letter to obtain short-term unsecured bridge financing of up to $200,000 that was undrawn and subsequently terminated when we completed the public offering of our Class A common stock on June 16, 2023. Net proceeds from the public equity offering completed on June 16, 2023, together with cash and cash equivalents, were used to fund the Twin Bridges Acquisition. See Note 14, Stockholders' Equity for further disclosure regarding the public offering.

As of December 31, 2023, we are party to the Amended and Restated Credit Agreement, which provides for a $350,000 aggregate principal amount Term Loan Facility and a $300,000 Revolving Credit Facility, with a $75,000 sublimit for letters of credit, and a $430,000 2023 Term Loan Facility (collectively, the "Credit Facility"). We have the right to request, at our discretion, an increase in the amount of loans under the Credit Facility by an aggregate amount of $125,000, subject to further increase based on the terms and conditions set forth in the Amended and Restated Credit Agreement. The Credit Facility has a 5-year term that matures in December 2026. The Credit Facility shall bear interest, at our election, at Term SOFR, including a secured overnight financing rate adjustment of 10 basis points, or at a base rate, in each case plus or minus any sustainable rate adjustment of up to positive or negative 4.0 basis points per annum, plus an applicable interest rate margin based upon our consolidated net leverage ratio as follows:

Term SOFR Loans

Base Rate Loans

Term Loan Facility

1.125% to 2.125%

0.125% to 1.125%

Revolving Credit Facility

1.125% to 2.125%

0.125% to 1.125%

2023 Term Loan Facility

1.625% to 2.625%

0.625% to 1.625%

A commitment fee will be charged on undrawn amounts of our Revolving Credit Facility based upon our consolidated net leverage ratio in the range of 0.20% to 0.40% per annum, plus a sustainability adjustment of up to positive or negative 1.0 basis point per annum. The Amended and Restated Credit Agreement provides that Term SOFR is subject to a zero percent floor. We are also required to pay a fronting fee for each letter of credit of 0.25% per annum. Interest under the Amended and Restated Credit Agreement is subject to increase by 2.00% per annum during the continuance of a payment default and may be subject to increase by 2.00% per annum during the continuance of any other event of default. The Credit Facility is guaranteed jointly and severally, fully and unconditionally by all of our significant wholly-owned subsidiaries and secured by substantially all of our assets. As of December 31, 2023, further advances were available under the Credit Facility in the amount of $272,267. The available amount is net of outstanding irrevocable letters of credit totaling $27,733, and as of December 31, 2023 no amount had been drawn.

The Amended and Restated Credit Agreement requires us to maintain a minimum interest coverage ratio and a maximum consolidated net leverage ratio, to be measured at the end of each fiscal quarter. In addition to these financial covenants, the Amended and Restated Credit Agreement contains a number of important customary affirmative and negative covenants which restrict, among other things, our ability to sell assets, incur additional debt, create liens, make investments, and pay dividends. As of December 31, 2023, we were in compliance with the covenants contained in the Amended and Restated Credit Agreement. An event of default under any of our debt agreements could permit some of our lenders, including the lenders under the Credit Facility, to declare all amounts borrowed from them to be immediately due and payable, together with accrued and unpaid interest, or, in the case of the Credit Facility, terminate the commitment to make further credit extensions thereunder, which could, in turn, trigger cross-defaults under other debt obligations. If we were unable to repay debt to our lenders or were otherwise in default under any provision governing our outstanding debt obligations, our secured lenders could proceed against us and against the collateral securing that debt.

Tax-Exempt Financings

Industrial revenue bonds are tax-exempt municipal debt securities issued by a government agency on our behalf and sold only to qualified institutional buyers. As of December 31, 2023, we had outstanding $232.0 million aggregate principal amount of tax-exempt bonds in the states of New York, Vermont, Maine and New Hampshire (collectively, the "Industrial Revenue Bonds"), which are unsecured and guaranteed jointly and severally, fully and unconditionally by all of our significant wholly-owned subsidiaries, and require interest payments semi-annually. The Industrial Revenue Bonds have fixed rate interest periods. At the end of each respective fixed rate interest period, the corresponding tax-exempt bond may be converted to a variable rate interest period or remarketed over a new fixed rate interest period. We borrowed the proceeds of the Industrial Revenue Bonds to finance or reimburse certain qualified capital projects and other costs in each respective state of issuance as defined in the related offering memorandum and indenture.

In fiscal year 2023, we completed the issuance of $35,000 aggregate principal amount of New York Bonds 2020R-2 and in fiscal year 2022 we completed the issuance of $35,000 aggregate principal amount of Vermont Bonds 2022A-1.

Interest Expense

The components of interest expense are as follows:


	Fiscal Year Ended December 31,
	2023		2022		2021
Interest expense on long-term debt and finance leases	$	44,836	$	21,691	$	19,201
Amortization of debt issuance costs (1)	2,962		1,903		2,288
Letter of credit fees	423		458		458
Less: capitalized interest	(643)		(330)		(718)
Total interest expense	$	47,578	$	23,722	$	21,229

Loss from Termination of Bridge Financing

In the fiscal year ended December 31, 2023, we wrote-off the unamortized debt issuance costs and recognized a loss from termination of bridge financing upon the extinguishment of both a secured bridge financing agreement in connection with the GFL Acquisition of $3,718, and an unsecured bridge financing agreement in connection with the Twin Bridges Acquisition of $4,473.

Cash Flow Hedges

Our strategy to reduce exposure to interest rate risk involves entering into interest rate derivative agreements to hedge against adverse movements in interest rates related to the variable rate portion of our long-term debt. We have designated these derivative instruments as highly effective cash flow hedges, and therefore the change in fair value is recorded in our stockholders’ equity as a component of accumulated other comprehensive income and included in interest expense at the same time as interest expense is affected by the hedged transactions. Differences paid or received over the life of the agreements are recorded as additions to or reductions of interest expense on the underlying debt and included in cash flows from operating activities.

A summary of the changes to the notional amount of interest rate derivative agreements follows:


	Active		Forward Starting		Total
Balance, December 31, 2021	$	195,000	$	85,000	$	280,000

Commencements	65,000		(65,000)		—
Maturities	(70,000)		—		(70,000)
Balance, December 31, 2022 (1)	190,000		20,000		210,000
Additions	390,000		—		390,000
Commencements	20,000		(20,000)		—
Maturities	(85,000)		—		(85,000)
Balance, December 31, 2023 (2)	$	515,000	$	—	$	515,000

A summary of the effect of cash flow hedges related to derivative instruments on the consolidated balance sheets follows:


		Fair Value
	Balance Sheet Location	December 31, 2023		December 31, 2022
Interest rate swaps	Other current assets	$	5,951	$	4,345
Interest rate swaps	Other non-current assets	4,413		7,461
Total		$	10,364	$	11,806


Interest rate swaps	Other long-term liabilities	$	11,762	$	—


Interest rate swaps	Accumulated other comprehensive (loss) income, net	$	(1,398)	$	11,806
Interest rate swaps - tax effect	Accumulated other comprehensive (loss) income, net	318		(4,264)
		$	(1,080)	$	7,542

Fair Value of Debt

As of December 31, 2023, the fair value of the Industrial Revenue Bonds was approximately $226,756 and the carrying value was $232,000. The fair value of the Industrial Revenue Bonds is considered to be Level 2 within the fair value hierarchy as the fair value is determined using market approach pricing provided by a third-party that utilizes pricing models and pricing systems, mathematical tools and judgment to determine the evaluated price for the security based on the market information of each of the bonds or securities with similar characteristics.

As of December 31, 2023, the carrying values of our Term Loan Facility and 2023 Term Loan Facility were $350,000 and $419,250, respectively, and the carrying value of our Revolving Credit Facility was zero dollars. Their fair values are based on current borrowing rates for similar types of borrowing arrangements, or Level 2 inputs, and approximate their carrying values.

Although we have determined the estimated fair value amounts of the Industrial Revenue Bonds using available market information and commonly accepted valuation methodologies, a change in available market information, and/or the use of different assumptions and/or estimation methodologies could have a material effect on the estimated fair values. These amounts have not been revalued, and current estimates of fair value could differ significantly from the amounts presented.

Future Maturities of Debt

Aggregate principal maturities of debt as of December 31, 2023 for each of the next five fiscal years and thereafter are as follows:



Fiscal year ending December 31, 2024	$	35,781
Fiscal year ending December 31, 2025	66,455
Fiscal year ending December 31, 2026	724,288
Fiscal year ending December 31, 2027	6,965
Fiscal year ending December 31, 2028	6,566
Thereafter	214,491
	$	1,054,546

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 470
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//470/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1E

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

+ Details

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Asset Impairments (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Goodwill impairment incurred	$ 0	$ 0	$ 0
Impairment of investments	$ 0	$ 0	$ 0
Mid-Atlantic
Segment Reporting Information [Line Items]
Percentage of fair value in excess of carrying amount	30.00%
Eastern
Segment Reporting Information [Line Items]
Percentage of fair value in excess of carrying amount	10.00%
Western
Segment Reporting Information [Line Items]
Percentage of fair value in excess of carrying amount	10.00%
Resource Solutions
Segment Reporting Information [Line Items]
Percentage of fair value in excess of carrying amount	10.00%

PROPERTY AND EQUIPMENT (Tables)

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

Schedule of Components of Property and Equipment

We provide for depreciation and amortization using the straight-line method by charges to operations in amounts that allocate the cost of the assets over their estimated useful lives as follows:


Asset Classification						Estimated Useful Life
Buildings and improvements						10-30 years
Machinery and equipment						5-10 years
Rolling stock						5-10 years
Containers						5-12 years
Furniture and Fixtures						3-8 years

A summary of property and equipment is as follows:


	December 31,
	2023		2022
Land	$	47,863	$	37,321
Landfills	786,130		730,914
Finance lease right-of-use assets	101,770		90,362
Buildings and improvements	262,204		209,234
Machinery and equipment	287,175		243,359
Rolling stock	396,247		276,282
Containers	266,705		197,834
Total property and equipment (1)	2,148,094		1,785,306
Less: accumulated depreciation and amortization	(1,167,541)		(1,064,756)
Property and equipment, net	$	980,553	$	720,550

BUSINESS COMBINATIONS - Schedule of Unaudited Pro forma Combined Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Combination and Asset Acquisition [Abstract]
Revenues	$ 1,436,871	$ 1,412,377	$ 1,303,556
Operating income	89,236	113,842	99,286
Net income	$ 28,507	$ 60,121	$ 36,200
Basic weighted average shares outstanding	55,174	51,623	51,312
Basic earnings per common share (in dollars per share)	$ 0.52	$ 1.16	$ 0.71
Diluted weighted average shares outstanding	55,274	51,767	51,515
Diluted earnings per common share (in dollars per share)	$ 0.52	$ 1.16	$ 0.70

LEASES - Schedule of Estimated Minimum Future Lease Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Operating Leases
Fiscal year ending December 31, 2024	$ 12,293
Fiscal year ending December 31, 2025	12,586
Fiscal year ending December 31, 2026	11,098
Fiscal year ending December 31, 2027	12,423
Fiscal year ending December 31, 2028	7,790
Thereafter	39,230
Total lease payments	95,420
Less: interest	(20,307)
Lease liability balance	75,113
Finance Leases
Fiscal year ending December 31, 2024	12,432
Fiscal year ending December 31, 2025	12,230
Fiscal year ending December 31, 2026	11,628
Fiscal year ending December 31, 2027	7,648
Fiscal year ending December 31, 2028	6,985
Thereafter	8,900
Total lease payments	59,823
Less: interest	(6,757)
Lease liability balance	$ 53,066	$ 49,813

BUSINESS COMBINATIONS (Tables)

12 Months Ended

Dec. 31, 2023

Business Combination and Asset Acquisition [Abstract]

Schedule of Purchase Price Paid for Acquisitions

A summary of the purchase price paid and the purchase price allocation for acquisitions follows:


	Fiscal Year Ended December 31,
	2023		2022		2021
Purchase Price:
Cash used in acquisitions, net of cash acquired	$	846,711	$	76,573	$	166,489


Other non-cash consideration	—		1,275		—
Open working capital settlements due from sellers	(2,873)		—		—
Holdbacks, additional consideration owed to sellers and contingent consideration	2,729		4,840		5,194
Total consideration	846,567		82,688		171,683
Allocated as follows:
Current assets (1)	19,524		7,644		7,218




Property and equipment:
Land	8,440		3,141		1,321
Finance lease right-of-use-assets	—		—		31,467
Buildings and improvements	28,411		8,576		11,046
Machinery, equipment and other	177,916		11,689		46,396
Operating lease right-of-use assets	11,786		405		6,500
Intangible assets:
Trade names	4,320		55		8,350
Covenants not-to-compete	30,860		2,424		1,807
Customer relationships	145,393		12,224		36,195
Other non-current assets	—		40		—
Deferred tax liability	(9,058)		—		—
Current liabilities	(21,417)		(3,812)		(6,014)





Other long-term liabilities	(828)		(123)		—
Financing lease liabilities, less current portion	—		—		(10,535)
Operating lease liabilities, less current portion	(9,939)		(282)		—

Fair value of assets acquired and liabilities assumed	385,408		41,981		133,751
Excess purchase price to be allocated to goodwill	$	461,159	$	40,707	$	37,932

(1)Includes contract receivables in fiscal year 2023, 2022 and 2021 of $17,002, $6,806 and $5,340, respectively.

Schedule of Unaudited Pro forma Combined Information


	Fiscal Year Ended December 31,
	2023		2022		2021
Revenues	$	1,436,871	$	1,412,377	$	1,303,556
Operating income	$	89,236	$	113,842	$	99,286
Net income	$	28,507	$	60,121	$	36,200

Basic earnings per share attributable to common stockholders:
Basic weighted average shares outstanding	55,174		51,623		51,312
Basic earnings per common share	$	0.52	$	1.16	$	0.71
Diluted earnings per share attributable to common stockholders:
Diluted weighted average shares outstanding	55,274		51,767		51,515
Diluted earnings per common share	$	0.52	$	1.16	$	0.70

INCOME TAXES - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Accrued expenses and reserves	$ 49,339	$ 43,437
Net operating loss carryforwards	30,165	13,398
General business and state tax credit carryforwards	6,862	6,987
Interest expense limitation	6,690	0
Stock awards	2,690	2,728
Unrealized loss on swaps	375	0
Other	1,567	2,419
Total deferred tax assets	97,688	68,969
Less: valuation allowance	(5,580)	(4,668)
Total deferred tax assets after valuation allowance	92,108	64,301
Deferred tax liabilities:
Tax over book depreciation of property and equipment	(58,927)	(21,561)
Amortization of intangibles	(22,540)	(17,252)
Unrealized gain on swaps	0	(3,022)
Other	(44)	0
Total deferred tax liabilities	(81,511)	(41,835)
Net deferred tax asset	$ 10,597	$ 22,466

GOODWILL AND INTANGIBLE ASSETS - Estimated Future Amortization Expense (Detail) $ in Thousands	Dec. 31, 2023 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Fiscal year ending December 31, 2024	$ 47,387
Fiscal year ending December 31, 2025	43,388
Fiscal year ending December 31, 2026	38,645
Fiscal year ending December 31, 2027	34,149
Fiscal year ending December 31, 2028	29,166
Thereafter	$ 48,694

DEBT - Variable Rate Margins (Details)	12 Months Ended
DEBT - Variable Rate Margins (Details)	Dec. 31, 2023
Term Loan A Facility ("Term Loan Facility") due December 2026; bearing interest at 7.083% as of December 31, 2023 \| SOFR \| Minimum \| Secured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	1.125%
Term Loan A Facility ("Term Loan Facility") due December 2026; bearing interest at 7.083% as of December 31, 2023 \| SOFR \| Maximum \| Secured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	2.125%
Term Loan A Facility ("Term Loan Facility") due December 2026; bearing interest at 7.083% as of December 31, 2023 \| Base Rate \| Minimum \| Secured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	0.125%
Term Loan A Facility ("Term Loan Facility") due December 2026; bearing interest at 7.083% as of December 31, 2023 \| Base Rate \| Maximum \| Secured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	1.125%
Revolving Credit Facility \| SOFR \| Minimum \| Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate	1.125%
Revolving Credit Facility \| SOFR \| Maximum \| Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate	2.125%
Revolving Credit Facility \| Base Rate \| Minimum \| Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate	0.125%
Revolving Credit Facility \| Base Rate \| Maximum \| Line of Credit
Debt Instrument [Line Items]
Basis spread on variable rate	1.125%
Term Loan A Facility ("2023 Term Loan Facility") due December 2026; bearing interest at 7.581% as of December 31, 2023 \| SOFR \| Minimum \| Secured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	1.625%
Term Loan A Facility ("2023 Term Loan Facility") due December 2026; bearing interest at 7.581% as of December 31, 2023 \| SOFR \| Maximum \| Secured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	2.625%
Term Loan A Facility ("2023 Term Loan Facility") due December 2026; bearing interest at 7.581% as of December 31, 2023 \| Base Rate \| Minimum \| Secured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	0.625%
Term Loan A Facility ("2023 Term Loan Facility") due December 2026; bearing interest at 7.581% as of December 31, 2023 \| Base Rate \| Maximum \| Secured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	1.625%

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Landfill and Lease Accounting (Detail)	12 Months Ended
	Dec. 31, 2023 USD ($) agreement	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Property, Plant and Equipment [Line Items]
Capitalized interest	$ 643,000	$ 330,000	$ 718,000
Closure and post-closure costs incurrence period	30 years
Estimate of inflation rate	2.40%
Accretion expense	$ 9,529,000	7,565,000
Number of operation and management agreements entered into \| agreement	3
Closure and post closure costs
Property, Plant and Equipment [Line Items]
Accretion expense	$ 9,529,000	7,565,000	$ 6,775,000
Surety bond	241,728,000	231,871,000
Letters of credit	$ 0	$ 0
Discount rate \| Minimum
Property, Plant and Equipment [Line Items]
Asset retirement obligation measurement input	6.10%
Discount rate \| Maximum
Property, Plant and Equipment [Line Items]
Asset retirement obligation measurement input	10.00%

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Schedule of Components of Property and Equipment

We provide for depreciation and amortization using the straight-line method by charges to operations in amounts that allocate the cost of the assets over their estimated useful lives as follows:


Asset Classification						Estimated Useful Life
Buildings and improvements						10-30 years
Machinery and equipment						5-10 years
Rolling stock						5-10 years
Containers						5-12 years
Furniture and Fixtures						3-8 years

A summary of property and equipment is as follows:


	December 31,
	2023		2022
Land	$	47,863	$	37,321
Landfills	786,130		730,914
Finance lease right-of-use assets	101,770		90,362
Buildings and improvements	262,204		209,234
Machinery and equipment	287,175		243,359
Rolling stock	396,247		276,282
Containers	266,705		197,834
Total property and equipment (1)	2,148,094		1,785,306
Less: accumulated depreciation and amortization	(1,167,541)		(1,064,756)
Property and equipment, net	$	980,553	$	720,550

STOCKHOLDERS' EQUITY (Tables)

12 Months Ended

Dec. 31, 2023

Equity [Abstract]

Schedule of Stock Option Activity

A summary of stock option activity is as follows:


	Stock Options	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value
Outstanding, December 31, 2022	129	$	55.60
Granted	18	$	79.72
Exercised	(18)	$	4.88
Forfeited or expired	—	$	—

Outstanding, December 31, 2023	129	$	66.03	7.5	$	2,504
Exercisable, December 31, 2023	49	$	40.60	5.2	$	2,177

Schedule of Restricted Stock, Restricted Stock Unit and Performance Stock Unit Activity

A summary of restricted stock award, restricted stock unit and performance stock unit activity is as follows:


	Restricted Stock Awards, Restricted Stock Units, and Performance Stock Units (1)	Weighted Average Grant Price		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value
Outstanding, December 31, 2022	169	$	75.52
Granted	121	$	80.99
Class A common stock vested	(101)	$	65.21
Forfeited or canceled	(8)	$	77.77
Outstanding, December 31, 2023	181	$	84.82	2.0	$	15,474
Unvested, December 31, 2023	288	$	87.35	1.9	$	24,593

Schedule of Accumulated Other Comprehensive Income (Loss)

The changes in the balances of each component of accumulated other comprehensive (loss) income, net of tax are as follows:


	Interest Rate Swaps
Balance as of December 31, 2020	$	(11,517)

Other comprehensive income before reclassifications	3,737
Amounts reclassified from accumulated other comprehensive loss	4,763
Income tax provision related to items in other comprehensive income	(2,086)
Other comprehensive income	6,414
Balance as of December 31, 2021	(5,103)

Other comprehensive income before reclassifications	15,297
Amounts reclassified from accumulated other comprehensive loss	1,443
Income tax provision related to items in other comprehensive income	(4,095)
Other comprehensive income	12,645
Balance as of December 31, 2022	7,542

Other comprehensive loss before reclassifications	(6,843)
Amounts reclassified from accumulated other comprehensive loss	(6,361)
Income tax benefit related to items in other comprehensive loss	4,582
Other comprehensive loss	(8,622)
Balance as of December 31, 2023	$	(1,080)

Schedule of Reclassification Out of Accumulated Other Comprehensive Income (Loss)

A summary of reclassifications out of accumulated other comprehensive (loss) income, net of tax for fiscal years 2023, 2022 and 2021 is as follows:


	Fiscal Year Ended December 31,
	2023		2022		2021
Details About Accumulated Other Comprehensive (Loss) Income, Net of Tax Components	Accumulated Other Comprehensive (Loss) Income, Net of Tax						Affected Line Item in the Consolidated Statements of Operations
Interest rate swaps	$	(6,361)	$	1,443	$	4,763	Interest expense
	6,361		(1,443)		(4,763)		Income before income taxes
	2,633		98		(1,142)		Provision for income taxes
	$	3,728	$	(1,541)	$	(3,621)	Net income