Casella Waste Systems (CWST) 10-K 18 Feb 25 2024 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2024	Jan. 31, 2025	Jun. 28, 2024
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2024
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			$ 5.6
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 2025 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, 2024
Entity Central Index Key	0000911177
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Amendment Flag	false
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		62,370,275
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		988,200

AUDIT INFORMATION

AUDIT INFORMATION	12 Months Ended
	Dec. 31, 2024
Audit Information [Abstract]
Auditor name	RSM US LLP
Auditor location	Boston, Massachusetts
Auditor firm ID	49

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
CURRENT ASSETS:
Cash, cash equivalents and restricted cash	$ 383,303	$ 220,912
Accounts receivable, net of allowance for credit losses of $8,515 and $4,066, respectively	165,917	157,324
Refundable income taxes	9,286	3,089
Prepaid expenses	23,047	17,223
Inventory	21,539	17,859
Other current assets	10,213	9,918
Total current assets	613,305	426,325
Property and equipment, net of accumulated depreciation and amortization of $1,302,324 and $1,167,541, respectively	1,164,815	980,553
Operating lease right-of-use assets	98,050	100,844
Goodwill	1,002,266	735,670
Intangible assets, net	313,468	241,429
Restricted assets	2,499	2,203
Cost method investments	10,967	10,967
Deferred income taxes	0	11,224
Other non-current assets	24,698	26,255
Total assets	3,230,068	2,535,470
CURRENT LIABILITIES:
Current maturities of debt	42,619	35,781
Current operating lease liabilities	10,291	9,039
Accounts payable	111,087	116,794
Accrued payroll and related expenses	32,620	22,657
Accrued interest	2,120	3,886
Contract liabilities	50,690	31,472
Current accrued capping, closure and post-closure costs	3,224	10,773
Other accrued liabilities	54,666	48,456
Total current liabilities	307,317	278,858
Debt, less current portion	1,090,632	1,007,662
Operating lease liabilities, less current portion	64,449	66,074
Accrued capping, closure and post-closure costs, less current portion	169,006	123,131
Deferred income taxes	19,089	627
Other long-term liabilities	28,736	37,327
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY:
Additional paid-in capital	1,679,878	1,168,812
Accumulated deficit	(132,985)	(146,521)
Accumulated other comprehensive income (loss), net of tax	3,312	(1,080)
Total stockholders' equity	1,550,839	1,021,791
Total liabilities and stockholders' equity	3,230,068	2,535,470
Class A Common Stock
STOCKHOLDERS' EQUITY:
Common stock	624	570
Class B Common Stock
STOCKHOLDERS' EQUITY:
Common stock	$ 10	$ 10

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) vote $ / shares shares	Dec. 31, 2023 USD ($) vote $ / shares shares
Accounts receivable - trade, allowance for credit losses | $	$ 8,515	$ 4,066
Accumulated depreciation and amortization | $	$ 1,302,324	$ 1,167,541
Class A Common Stock
Common stock, par value (in dollars per share) | $ / shares	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	62,370,000	57,007,000
Common stock, shares outstanding (in shares)	62,370,000	57,007,000
Votes per share held (in votes) | vote	1
Class B Common Stock
Common stock, par value (in dollars per share) | $ / shares	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000	1,000,000
Common stock, shares issued (in shares)	988,000	988,000
Common stock, shares outstanding (in shares)	988,000	988,000
Votes per share held (in votes) | vote	10	10

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Revenues	$ 1,557,283	$ 1,264,542	$ 1,085,089
Operating expenses:
Cost of operations	1,027,336	832,038	723,117
General and administration	190,754	155,847	133,419
Depreciation and amortization	234,907	170,705	126,351
Expense from acquisition activities	24,879	15,038	4,613
Southbridge Landfill closure charge	8,385	467	1,436
Landfill capping (recovery) charge - veneer failure	(1,739)	3,870	0
Legal settlement	0	6,150	0
Environmental remediation charge	0	0	759
Total operating expenses	1,484,522	1,184,115	989,695
Operating income	72,761	80,427	95,394
Other expense (income):
Interest income	(10,428)	(10,741)	(709)
Interest expense	62,411	47,578	23,722
Debt modification expense	1,396	0	0
Loss from termination of bridge financing	0	8,191	0
Other income	(1,666)	(1,646)	(2,585)
Other expense, net	51,713	43,382	20,428
Income before income taxes	21,048	37,045	74,966
Provision for income taxes	7,512	11,646	21,887
Net income	$ 13,536	$ 25,399	$ 53,079
Basic earnings per share attributable to common stockholders:
Weighted average common shares outstanding, basic (in shares)	59,576	55,174	51,623
Basic earnings per common share (in dollars per share)	$ 0.23	$ 0.46	$ 1.03
Diluted earnings per share attributable to common stockholders:
Weighted average common shares outstanding, diluted (in shares)	59,681	55,274	51,767
Diluted earnings per common share (in dollars per share)	$ 0.23	$ 0.46	$ 1.03

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 13,536	$ 25,399	$ 53,079
Hedging activity:
Interest rate swap settlements	8,543	6,259	(1,662)
Interest rate swap amounts reclassified into interest expense	(8,442)	(6,361)	1,443
Unrealized gain (loss) resulting from changes in fair value of derivative instruments	6,088	(13,102)	16,959
Other comprehensive income (loss)	6,189	(13,204)	16,740
Tax effect related to items of other comprehensive income (loss)	1,797	(4,582)	4,095
Other comprehensive income (loss), net of tax	4,392	(8,622)	12,645
Comprehensive income	$ 17,928	$ 16,777	$ 65,724

CONSOLIDATED STATEMENT OF STOCK

CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income ( Loss), 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, 2021	$ 422,457	$ 652,045	$ (224,999)	$ (5,103)		$ 504		$ 10
Beginning balance (in shares) at Dec. 31, 2021						50,423,000		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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A common stock - equity offering, net of stock issuance costs	496,245	496,193				$ 52
Issuance of Class A common stock - equity offering, net of stock issuance costs (in shares)						5,175,000
Issuances of Class A common stock	2,689	2,687				$ 2
Issuances of Class A common stock (in shares)						188,000
Stock-based compensation	12,186	12,186
Net income	13,536		13,536
Hedging activity	4,392			4,392
Ending balance at Dec. 31, 2024	$ 1,550,839	$ 1,679,878	$ (132,985)	$ 3,312		$ 624		$ 10
Ending balance (in shares) at Dec. 31, 2024					62,370,000	62,370,000	988,000	988,000

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash Flows from Operating Activities:
Net income	$ 13,536	$ 25,399	$ 53,079
net income to net cash provided by operating activities:
Depreciation and amortization	234,907	170,705	126,351
Interest accretion on landfill and environmental remediation liabilities	11,601	9,885	8,008
Amortization of debt issuance costs	2,960	2,962	1,903
Stock-based compensation	12,186	9,084	8,155
Operating lease right-of-use assets expense	17,784	15,318	13,804
Other items and charges, net	12,980	708	737
Loss from termination of bridge financing	0	8,191	0
Landfill capping (recovery) charge - veneer failure	(889)	3,021	0
Deferred income taxes	6,894	7,392	16,527
Changes in assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable	1,253	(39,436)	(7,101)
Landfill operating lease contract expenditures	(5,486)	(5,496)	(5,486)
Accounts payable	(13,634)	41,592	11,075
Prepaid expenses, inventories and other assets	(12,519)	(8,172)	(11,054)
Accrued expenses, contract liabilities and other liabilities	(218)	(8,061)	1,316
Net cash provided by operating activities	281,355	233,092	217,314
Cash Flows from Investing Activities:
Acquisitions, net of cash acquired	(468,628)	(851,839)	(78,197)
Additions to intangible assets	(280)	0	0
Additions to property and equipment	(203,227)	(154,907)	(130,960)
Proceeds from sale of cost method investment	0	0	1,637
Proceeds from sale of property and equipment	1,380	1,110	600
Proceeds from property insurance settlement	146	0	0
Net cash used in investing activities	(670,609)	(1,005,636)	(206,920)
Cash Flows from Financing Activities:
Proceeds from debt borrowings	846,750	465,000	88,200
Principal payments on debt	(783,684)	(26,257)	(59,211)
Payments of debt issuance costs	(6,619)	(12,759)	(1,232)
Payments of contingent consideration	0	0	(1,000)
Proceeds from the exercise of share based awards	349	89	192
Proceeds from the public offering of Class A Common Stock	496,245	496,231	0
Payments of debt modification costs	(1,396)	0	0
Net cash provided by financing activities	551,645	922,304	26,949
Net increase in cash, cash equivalents and restricted cash	162,391	149,760	37,343
Cash, cash equivalents and restricted cash, beginning of period	220,912	71,152	33,809
Cash, cash equivalents and restricted cash, end of period	383,303	220,912	71,152
Supplemental Disclosures of Cash Flow Information:
Interest	61,217	43,588	21,003
Income tax payments	6,776	10,109	2,798
Supplemental Disclosures of Non-Cash Investing and Financing Activities:
Non-current assets acquired through long-term financing obligations	$ 30,551	$ 12,322	$ 11,919

BASIS OF PRESENTATION

BASIS OF PRESENTATION	12 Months Ended
	Dec. 31, 2024
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 ten states: Vermont, New Hampshire, New York, Massachusetts, Connecticut, Maine, Pennsylvania, New Jersey, Delaware and Maryland, with our headquarters located in Rutland, Vermont. 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 CHANGES

ACCOUNTING CHANGES	12 Months Ended
	Dec. 31, 2024
Accounting Changes and Error Corrections [Abstract]
ACCOUNTING CHANGES	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 in the fiscal year ended December 31, 2024 (“fiscal year 2024”): Standard Description Effect on the Financial Statements or Other 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 adopted this guidance effective December 31, 2024 and its adoption had an impact on our reportable operating segment disclosures within our consolidated financial statements and accompanying notes. See Note 20, Segment Reporting for enhanced disclosure. The following table provides a brief description of recent ASUs to the ASC issued by the FASB that are pending adoption as of December 31, 2024 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 Accounting standards issued pending adoption as of December 31, 2024 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. ASU No. 2024-03: Improvements to Income Statement - Expense Disaggregation Disclosures Requires entities to provide additional disclosure related to more detailed information about specific types of expenses contained in commonly presented expense captions on the statements of operations. We are currently assessing the provisions of this guidance and expect that its adoption will have an impact on certain expense category disclosures within our consolidated financial statements and accompanying notes. This guidance is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	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, asset impairments, if applicable, goodwill recoverability assessment, accounts receivable 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. 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, 2024, 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 quarterly 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 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 year 2024, the fiscal year ended December 31, 2023 (“fiscal year 2023”) and the fiscal year ended December 31, 2022 (“fiscal year 2022”) was $1,085, $643 and $330, 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 (2.6% as of December 31, 2024). 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, 2024 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 $11,350, $9,529 and $7,565 in fiscal years 2024, 2023 and 2022, 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 17, Other Items and Charges for disclosure about the write-off and subsequent partial recovery 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”) that occurred in fiscal year 2023. 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, 2024 and December 31, 2023 totaled $266,446 and $241,728, respectively. There are no letters of credit securing closure and post-closure obligations as of December 31, 2024 and December 31, 2023. See Note 14, 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, 2024 and December 31, 2023, 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, 2024 and December 31, 2023, 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 include cash, cash equivalents and restricted cash, 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, 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 11, Debt and Note 14, 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 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 17, 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 12, 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 2024, our maximum exposure per individual event under the workers’ compensation plan was $1,500. In fiscal year 2024, our minimum and maximum exposure per individual event under the automobile plan were up to $2,000 and $4,200, 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 $24,949 and $22,427 as of December 31, 2024 and December 31, 2023, 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 16, 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 11, Debt for further disclosure about interest rate derivatives and Note 14, 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 con

REVENUE RECOGNITION

REVENUE RECOGNITION	12 Months Ended
	Dec. 31, 2024
Revenue from Contract with Customer [Abstract]
REVENUE RECOGNITION	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 generation and sale of renewable natural gas (“RNG”) from a landfill RNG facility; 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, 2024 Eastern Western Mid-Atlantic Resource Solutions Total Revenues Collection $ 302,585 $ 441,386 $ 217,813 $ — $ 961,784 Landfill 30,541 64,204 — — 94,745 Transfer station 68,229 61,430 1,711 — 131,370 Transportation 5,298 15,305 — — 20,603 Landfill gas-to-energy 1,661 6,297 — — 7,958 Processing 8,364 2,592 — 130,459 141,415 National Accounts — — — 199,408 199,408 Total revenues $ 416,678 $ 591,214 $ 219,524 $ 329,867 $ 1,557,283 Transferred at a point-in-time $ 471 $ 2,516 $ — $ 58,273 $ 61,260 Transferred over time 416,207 588,698 219,524 271,594 1,496,023 Total revenues $ 416,678 $ 591,214 $ 219,524 $ 329,867 $ 1,557,283 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 station 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 station 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.

BUSINESS COMBINATIONS

BUSINESS COMBINATIONS	12 Months Ended
	Dec. 31, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]
BUSINESS COMBINATIONS	BUSINESS COMBINATIONS In fiscal year 2024, we acquired eight businesses: four of which are in our Mid-Atlantic region, including the purchase of all the equity interests of Whitetail Disposal, Inc. and the assets of LMR Disposal, LLC, which together include collection operations in eastern Pennsylvania and western New Jersey; two of which are in our Western region, including the purchase of all equity interests of Royal Carting and Welsh Sanitation and related real estate assets, which consists of collection and transfer operations in the middle and lower Hudson Valley regions of New York as well as western Connecticut; and two of which are tuck-in operations in our Eastern region. In fiscal year 2023, we acquired seven businesses: the equity interests of four wholly-owned subsidiaries of GFL Environmental Inc., which include solid waste collection, transfer and recycling operations in Pennsylvania, Maryland and Delaware (the “GFL Acquisition”); the assets of Consolidated Waste Services, LLC and its affiliates (dba Twin Bridges), 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. The operating results of these businesses acquired prior to December 31, 2024 have been included in the accompanying audited consolidated statements of operations from each date of acquisition, and each purchase price has been allocated to the net assets acquired based on fair values at the date of each acquisition with the residual amounts recorded as goodwill. 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 acquisition dates. Purchase price allocations are based on information existing at the acquisition dates or upon closing the transactions. 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 Goodwill acquired is primarily associated with the value of acquired businesses based on the current and anticipated operating performance of the business, in excess of the specific values allocated to other assets, new growth opportunities arising from the acquisitions, and expected synergies from combining the acquired businesses with our existing operations and implementing our operating strategies. Approximately $120,754 of goodwill associated with acquisitions completed in fiscal year 2024 is 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 2024 2023 2022 Purchase Price: Cash used in acquisitions, net of cash acquired of $11,687, $1,014, and $—, respectively $ 469,159 $ 846,711 $ 76,573 Other non-cash consideration — — 1,275 Working capital settlements due from sellers (2,987) (2,873) — Holdbacks and additional consideration due to sellers 1,689 2,729 4,840 Total consideration 467,861 846,567 82,688 Allocated as follows: Current assets (1) 15,992 19,524 7,644 Property and equipment: Land 7,026 8,440 3,141 Buildings and improvements 9,878 28,411 8,576 Machinery, equipment and other 89,995 177,916 11,689 Operating lease right-of-use assets 5,222 11,786 405 Intangible assets: Trade names 12,470 4,320 55 Covenants not-to-compete 10,997 30,860 2,424 Customer relationships 104,762 145,393 12,224 Other non-current assets — — 40 Deferred tax liability (20,392) (9,058) — Current liabilities (27,755) (21,417) (3,812) Other long-term liabilities — (828) (123) Operating lease liabilities, less current portion (5,092) (9,939) (282) Fair value of assets acquired and liabilities assumed 203,103 385,408 41,981 Excess purchase price to be allocated to goodwill $ 264,758 $ 461,159 $ 40,707 (1) Includes contract receivables in fiscal year 2024, 2023 and 2022 of $12,936, $17,002 and $6,806, respectively. Substantially all of contractual amounts are expected to be collected. Purchase price allocations are preliminary and subject to revision upon finalization of third-party valuations over each respective one-year measurement period. Accordingly, the purchase price allocations for fiscal year 2024 are subject to change. Amounts in the fiscal years 2023 and 2022 are preliminary as disclosed based on information existing at the acquisition dates or upon closing the transaction and have since been updated based upon the finalization of third-party valuations, including the value of certain tangible and intangible assets acquired. Unaudited pro forma combined information that shows our operational results as though each acquisition completed through December 31, 2024 had occurred as of January 1, 2022 is as follows: Fiscal Year Ended 2024 2023 2022 Revenues $ 1,699,991 $ 1,653,535 $ 1,629,041 Operating income $ 66,320 $ 79,815 $ 104,422 Net income $ 8,784 $ 21,111 $ 52,726 Basic earnings per share attributable to common stockholders: Basic weighted average shares outstanding 59,576 55,174 51,623 Basic earnings per common share $ 0.15 $ 0.38 $ 1.02 Diluted earnings per share attributable to common stockholders: Diluted weighted average shares outstanding 59,681 55,274 51,767 Diluted earnings per common share $ 0.15 $ 0.38 $ 1.02 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, 2022 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.

ACCOUNTS RECEIVABLE, NET OF ALL

ACCOUNTS RECEIVABLE, NET OF ALLOWANCE FOR CREDIT LOSSES	12 Months Ended
	Dec. 31, 2024
Credit Loss [Abstract]
ACCOUNTS RECEIVABLE, NET OF ALLOWANCE FOR CREDIT LOSSES	ACCOUNTS RECEIVABLE, NET OF ALLOWANCE FOR CREDIT LOSSES A summary of the changes to allowance for credit losses follows: Fiscal Year Ended 2024 2023 2022 Balance at beginning of period $ 4,066 $ 3,016 $ 3,276 Additions - charged to expense (1) 5,987 2,468 1,893 Additions - reserve for acquired receivables with credit deterioration 870 — — Deductions - write offs charged against the allowance, net of recoveries (2,408) (1,418) (2,153) Balance at end of period $ 8,515 $ 4,066 $ 3,016 (1) Includes a charge recorded in fiscal year 2024 in expense from acquisition activities for an increase in the reserve against accounts receivable of the businesses acquired in the GFL Acquisition as a result of our inability to pursue collections during the transition services period with the seller, resulting in accounts receivable aged beyond what is typical in our business. See Note 17, Other Items and Charges for disclosure regarding expense from acquisition activities.

PROPERTY AND EQUIPMENT

PROPERTY AND EQUIPMENT	12 Months Ended
	Dec. 31, 2024
Property, Plant and Equipment [Abstract]
PROPERTY AND EQUIPMENT	PROPERTY AND EQUIPMENT A summary of property and equipment is as follows: December 31, 2024 2023 Land $ 56,010 $ 47,863 Landfills 859,602 786,130 Finance lease right-of-use assets 128,159 101,770 Buildings and improvements 303,170 262,204 Machinery and equipment 318,391 287,175 Rolling stock 490,571 396,247 Containers 311,236 266,705 Total property and equipment (1) 2,467,139 2,148,094 Less: accumulated depreciation and amortization (1,302,324) (1,167,541) Property and equipment, net $ 1,164,815 $ 980,553 (1) Includes construction-in-process of $104,686 and $74,408 at December 31, 2024 and December 31, 2023, respectively, that have not been placed in service and, therefore, have not begun depreciating. Depreciation expense for fiscal years 2024, 2023 and 2022 was $133,928, $99,249 and $78,139, respectively. Landfill amortization expense for fiscal years 2024, 2023 and 2022 was $44,498, $40,419 and $31,619, respectively.

LEASES

LEASES	12 Months Ended
	Dec. 31, 2024
Leases [Abstract]
LEASES	LEASES A schedule of lease costs and other lease information follows: Fiscal Year Ended 2024 2023 Lease cost: Amortization of right-of-use assets $ 9,216 $ 7,383 Interest expense 2,594 1,840 Fixed lease cost - vehicles, equipment and property 8,021 6,292 Fixed lease cost - landfill operating leases 9,763 9,026 Fixed lease cost 17,784 15,318 Short-term lease cost 9,603 5,313 Variable lease cost 780 604 Total lease cost $ 39,977 $ 30,458 Other information: Cash paid for amounts included in the measurement of lease liabilities: Financing cash flows for finance leases $ 12,071 $ 8,981 Operating cash flows for operating leases $ 11,884 $ 10,578 Right-of-use assets obtained in exchange for new finance lease liabilities $ 28,723 $ 12,211 Right-of-use assets obtained in exchange for new operating lease liabilities $ 11,686 $ 19,796 December 31, 2024 Weighted-average remaining lease term - finance leases (years) 5.1 Weighted-average remaining lease term - operating leases (years) 9.9 Weighted-average discount rate - finance leases 4.6 % Weighted-average discount rate - operating leases 4.8 % Estimated minimum future lease obligations as of December 31, 2024 for each of the next five fiscal years and thereafter are as follows: Operating Leases Finance Leases Fiscal year ending December 31, 2025 $ 13,608 $ 19,951 Fiscal year ending December 31, 2026 12,719 15,367 Fiscal year ending December 31, 2027 11,669 11,399 Fiscal year ending December 31, 2028 8,926 10,750 Fiscal year ending December 31, 2029 8,656 8,571 Thereafter 40,069 14,366 Total lease payments 95,647 80,404 Less: interest (20,907) (10,742) Lease liability balance $ 74,740 $ 69,662
LEASES	LEASES A schedule of lease costs and other lease information follows: Fiscal Year Ended 2024 2023 Lease cost: Amortization of right-of-use assets $ 9,216 $ 7,383 Interest expense 2,594 1,840 Fixed lease cost - vehicles, equipment and property 8,021 6,292 Fixed lease cost - landfill operating leases 9,763 9,026 Fixed lease cost 17,784 15,318 Short-term lease cost 9,603 5,313 Variable lease cost 780 604 Total lease cost $ 39,977 $ 30,458 Other information: Cash paid for amounts included in the measurement of lease liabilities: Financing cash flows for finance leases $ 12,071 $ 8,981 Operating cash flows for operating leases $ 11,884 $ 10,578 Right-of-use assets obtained in exchange for new finance lease liabilities $ 28,723 $ 12,211 Right-of-use assets obtained in exchange for new operating lease liabilities $ 11,686 $ 19,796 December 31, 2024 Weighted-average remaining lease term - finance leases (years) 5.1 Weighted-average remaining lease term - operating leases (years) 9.9 Weighted-average discount rate - finance leases 4.6 % Weighted-average discount rate - operating leases 4.8 % Estimated minimum future lease obligations as of December 31, 2024 for each of the next five fiscal years and thereafter are as follows: Operating Leases Finance Leases Fiscal year ending December 31, 2025 $ 13,608 $ 19,951 Fiscal year ending December 31, 2026 12,719 15,367 Fiscal year ending December 31, 2027 11,669 11,399 Fiscal year ending December 31, 2028 8,926 10,750 Fiscal year ending December 31, 2029 8,656 8,571 Thereafter 40,069 14,366 Total lease payments 95,647 80,404 Less: interest (20,907) (10,742) Lease liability balance $ 74,740 $ 69,662

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND INTANGIBLE ASSETS	GOODWILL AND INTANGIBLE ASSETS A summary of the activity and balances related to goodwill by reportable operating segment is as follows: December 31, 2023 Acquisitions Business Combination Adjustments December 31, 2024 Eastern $ 73,893 $ 774 $ — $ 74,667 Western 285,056 92,825 704 378,585 Mid-Atlantic 332,247 171,159 946 504,352 Resource Solutions 44,474 — 188 44,662 Total $ 735,670 $ 264,758 $ 1,838 $ 1,002,266 December 31, 2022 Acquisitions Business Combination 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 A summary of intangible assets is as follows: Covenants Customer Relationships Trade Names Total Balance, December 31, 2024 Intangible assets $ 71,568 $ 377,600 $ 25,795 $ 474,963 Less accumulated amortization (34,398) (115,305) (11,792) (161,495) $ 37,170 $ 262,295 $ 14,003 $ 313,468 Covenants Customer Relationships Trade Names Total Balance, December 31, 2023 Intangible assets $ 61,573 $ 272,571 $ 13,325 $ 347,469 Less accumulated amortization (26,645) (72,227) (7,168) (106,040) $ 34,928 $ 200,344 $ 6,157 $ 241,429 Intangible amortization expense for fiscal years 2024, 2023 and 2022 was $56,481, $31,037 and $16,593, respectively. Based on the amortizable intangible assets recorded in the consolidated balance sheets at December 31, 2024, intangible amortization expense for each of the next five fiscal years and thereafter is estimated as follows: Fiscal year ending December 31, 2025 $ 67,846 Fiscal year ending December 31, 2026 $ 60,006 Fiscal year ending December 31, 2027 $ 52,478 Fiscal year ending December 31, 2028 $ 44,749 Fiscal year ending December 31, 2029 $ 34,086 Thereafter $ 54,303

FINAL CAPPING, CLOSURE AND POST

FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS	12 Months Ended
	Dec. 31, 2024
Asset Retirement Obligation Disclosure [Abstract]
FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS	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 2024 2023 Beginning balance $ 133,904 $ 113,678 Obligations incurred 7,093 5,447 Revisions in estimates (1) 29,537 14,030 Accretion expense 11,350 9,529 Obligations settled (2) (8,765) (11,801) (Recovery) write-off of capping payments (3) (889) 3,021 Ending balance $ 172,230 $ 133,904 (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. Fiscal year 2024 includes $8,385 related to the revision in estimates of the post-closure liability for the Town of Southbridge, Massachusetts landfill (“Southbridge Landfill”), related to the final closure permit. See Note 17, Other Items and Charges for further disclosure over the Southbridge Landfill revision. (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 historical payments associated with capping work that was deemed no longer viable due to a veneer failure at the Ontario County Landfill, which we operate, that occurred in fiscal year 2023, and subsequent partial recovery in fiscal year 2024 after an engineering evaluation determined that a portion of the affected area was still viable. See Note 17, Other Items and Charges for additional disclosure.

DEBT

DEBT	12 Months Ended
	Dec. 31, 2024
Debt And Derivatives Disclosure [Abstract]
DEBT	DEBT A summary of debt is as follows: December 31, 2024 2023 Senior Secured Credit Facility: Term loan A facility (“Term Loan Facility”) payable quarterly beginning in the fiscal year ended December 31, 2027 with balance due September 2029; bearing interest at 5.967% as of December 31, 2024 $ 800,000 $ — Term loan A facility payable quarterly with balance due December 2026 amended and restated in September 2024 as the Term Loan Facility — 350,000 Term loan A facility payable quarterly with balance due December 2026 amended and restated in September 2024 as the Term Loan Facility — 419,250 Revolving credit facility (“Revolving Credit Facility”) due September 2029; bearing interest at term secured overnight financing rate (“Term SOFR”) plus 1.610% — — Revolving credit facility due December 2026 amended and restated in September 2024 as the Revolving Credit Facility — — 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 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 Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2024 (“FAME Bonds 2024”) due December 2047 - fixed rate interest period bearing interest at 4.625% through May 2035 45,000 — 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 69,662 53,066 Notes payable maturing through September 2028; bearing interest up to 8.1% 1,500 230 Principal amount of debt 1,148,162 1,054,546 Less—unamortized debt issuance costs 14,911 11,103 Debt less unamortized debt issuance costs 1,133,251 1,043,443 Less—current maturities of debt 42,619 35,781 Debt, less current portion $ 1,090,632 $ 1,007,662 Credit Facility In September 2024, we entered into a second amended and restated credit agreement (“Credit Agreement”), which amended and restated in its entirety our amended and restated credit agreement (“Existing Credit Agreement”). The Credit Agreement provides for a $800,000 aggregate principal amount Term Loan Facility and a $700,000 Revolving Credit Facility, with a $155,000 sublimit for letters of credit (collectively, the “Credit Facility”). The proceeds of the Credit Facility refinanced our term loans under the Existing Credit Agreement, and may be used for working capital, permitted acquisitions, investments and dividends and distributions, and for other general corporate purposes. The Existing Credit Agreement included a $430,000 aggregate principal amount Term Loan A Facility entered into in June 2023 to partially fund the GFL Acquisition. 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 $200,000, subject to further increase based on the terms and conditions set forth in the Credit Agreement. The Credit Facility has a 5-year term that matures in September 2029. The Credit Facility shall bear interest, at our election, at Term SOFR 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 Credit Facility 1.300% to 2.175% 0.300% to 1.175% 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 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 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, 2024, further advances were available under the Credit Facility in the amount of $675,403. The available amount is net of outstanding irrevocable letters of credit totaling $24,597, and as of December 31, 2024 no amount had been drawn. The 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 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, 2024, we were in compliance with the covenants contained in the 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, 2024, we had outstanding $277.0 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 2024, we completed the issuance of $45,000 aggregate principal amount of FAME Bonds 2024, $25,000 of which was restricted as of December 31, 2024 to be used for the repayment in full of FAME Bonds 2005R-3, which matured and were paid in January 2025. In fiscal year 2023, we completed the issuance of $35,000 aggregate principal amount of New York Bonds 2020R-2. Interest Expense The components of interest expense are as follows: Fiscal Year Ended 2024 2023 2022 Interest expense on long-term debt and finance leases $ 60,077 $ 44,836 $ 21,691 Amortization of debt issuance costs (1) 2,960 2,962 1,903 Letter of credit fees 459 423 458 Less: capitalized interest (1,085) (643) (330) Total interest expense $ 62,411 $ 47,578 $ 23,722 (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 2023. Debt Modification Expense In fiscal year 2024, we recognized debt modification expense of $1,396 associated with agent fees and other third-party costs we paid during the refinancing of our Credit Agreement. Loss from Termination of Bridge Financing In fiscal year 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 (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. A summary of the changes to the notional amount of interest rate derivative agreements follows: Active Forward Starting Total Balance, December 31, 2022 $ 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 515,000 — 515,000 Additions — — — Commencements — — — Maturities — — — Balance, December 31, 2024 (1) $ 515,000 $ — $ 515,000 (1) 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%. 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, December 31, Interest rate swaps Other current assets $ 3,606 $ 5,951 Interest rate swaps Other non-current assets 4,036 4,413 Total $ 7,642 $ 10,364 Interest rate swaps Other accrued liabilities $ 570 $ — Interest rate swaps Other long-term liabilities 2,282 11,762 Total $ 2,852 $ 11,762 Interest rate swaps Accumulated other comprehensive income (loss), net $ 4,790 $ (1,398) Interest rate swaps - tax effect Accumulated other comprehensive income (loss), net (1,478) 318 $ 3,312 $ (1,080) Fair Value of Debt As of December 31, 2024, the fair value of the Industrial Revenue Bonds was approximately $276,503 and the carrying value was $277,000. 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, 2024, the carrying value of our Term Loan Facility was $800,000 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, 2024 for each of the next five fiscal years and thereafter are as follows: Fiscal year ending December 31, 2025 $ 42,619 Fiscal year ending December 31, 2026 13,717 Fiscal year ending December 31, 2027 18,201 Fiscal year ending December 31, 2028 29,968 Fiscal year ending December 31, 2029 790,815 Thereafter 252,842 $ 1,148,162

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	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 $601 relating to our outstanding legal proceedings as of December 31, 2024. 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 17, 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. On March 18, 2024, the Supreme Court issued an order finding the appeal to be moot and vacating the Superior Court’s April 6, 2023 Order, resolving this matter. 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. North Country Environmental Services Letter of Deficiency On June 14, 2024, NCES received a Letter of Deficiency (the “Letter”) from DES concerning alleged violations related to leachate management and leachate data and reporting. The Letter required certain actions to correct the deficiencies on a prescribed timeline, and NCES has met the deadlines for information submission. NCES has entered into preliminary discussions with the New Hampshire Department of Justice concerning an administrative order and associated penalties relative to the deficiencies. We believe that a liability related to this matter is probable and, accordingly, have recorded an accrual as of December 31, 2024. 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, 2024 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, 2024 and 2023 follows: Twelve Months Ended 2024 2023 Beginning balance $ 5,889 $ 6,335 Accretion expense 95 100 Obligations settled (2) (452) (546) Ending balance 5,532 5,889 Less: current portion 1,597 1,662 Long-term portion $ 3,935 $ 4,227 (1) 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, 2024 for each of the next five fiscal years and thereafter are as follows: Fiscal year ending December 31, 2025 $ 1,599 Fiscal year ending December 31, 2026 281 Fiscal year ending December 31, 2027 278 Fiscal year ending December 31, 2028 304 Fiscal year ending December 31, 2029 297 Thereafter 3,406 Total $ 6,165 A reconciliation of the expected aggregate non-inflated, undiscounted environmental remediation liabilities to the amount recognized in our consolidated balance sheet at December 31, 2024 is as follows: Undiscounted liability $ 6,165 Less discount, net (633) Liability balance - December 31, 2024 $ 5,532 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. Cash, Cash Equivalents and Restricted Cash Restricted cash is included with cash and cash equivalents in our consolidated balance sheets. Our restricted cash consists of cash proceeds from the issuance of the FAME Bonds 2024 restricted to be used for the repayment in full of FAME Bonds 2005R-3 on its stated maturity in January 2025. See Note 11, Debt for disclosure regarding our industrial revenue bonds. A reconciliation of cash, cash equivalents and restricted cash is as follows: December 31, 2024 December 31, 2023 Cash and cash equivalents $ 358,303 $ 220,912 Restricted cash 25,000 — Cash, cash equivalents and restricted cash $ 383,303 $ 220,912

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
STOCKHOLDERS' EQUITY	STOCKHOLDERS' EQUITY Public Offering of Class A Common Stock On September 19, 2024, we completed a public offering of 5,175 shares of our Class A common stock at a public offering price of $100.00 per share. After deducting stock issuance costs, including underwriting discounts, commissions and offering expenses, the offering resulted in net proceeds of $496,245. The net proceeds from this offering were and are to be used to repay borrowings under our Revolving Credit Facility and are further available to fund acquisition activity and for general corporate purposes. 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 17, Other Items and Charges , and to repay borrowings and/or debt securities as discussed Note 11, 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, 2024 and December 31, 2023, we had no shares issued. Stock Based Compensation Stock Incentive Plans Amended and Restated 2016 Incentive Plan. In fiscal year 2024, our stockholders approved the amendment and restatement of our 2016 Incentive Plan (the “Amended 2016 Plan”). Under the Amended 2016 Plan, we may grant awards up to an aggregate amount of shares equal to the sum of: (A) 4,000 shares of Class A common stock (subject to adjustment in the event of stock splits and other similar events) which is comprised of: (i) 1,750 shares of Class A common stock reserved for the issuance in connection with the Amended 2016 Plan, plus (ii) 2,250 shares of Class A common stock originally reserved for issuance under the 2016 Incentive Plan; plus (B) such additional number of shares of Class A common stock (up to approximately 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, terminate or are otherwise surrendered, canceled, forfeited or repurchased by us. As of December 31, 2024, there were 2,205 Class A common stock equivalents available for future grant under the Amended 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 Weighted Aggregate Outstanding, December 31, 2023 129 $ 66.03 Granted — $ — Exercised (28) $ 12.48 Forfeited or expired — $ — Outstanding, December 31, 2024 101 $ 80.85 7.7 $ 2,518 Exercisable, December 31, 2024 42 $ 79.50 7.5 $ 1,102 During fiscal years 2024, 2023 and 2022, stock-based compensation expense for stock options was $579, $516 and $248, respectively. During fiscal years 2024, 2023 and 2022, the aggregate intrinsic value of stock options exercised was $2,625, $1,302 and $1,467, respectively. As of December 31, 2024, we had $1,528 of unrecognized stock-based compensation expense related to outstanding stock options to be recognized over a weighted average period of 2.9 years. 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 Weighted Average Aggregate Intrinsic Outstanding, December 31, 2023 181 $ 84.82 Granted 106 $ 99.61 Class A common stock vested (84) $ 88.60 Forfeited or canceled (6) $ 85.70 Outstanding, December 31, 2024 197 $ 91.14 1.9 $ 20,882 Unvested, December 31, 2024 327 $ 92.55 1.7 $ 34,625 (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 130 shares of Class A common stock currently included in unvested. The market-based performance stock unit grants that vested in fiscal year 2024 resulted in the issuance of 38 additional shares of Class A common stock. During fiscal years 2024, 2023 and 2022, stock-based compensation expense related to restricted stock awards, restricted stock units and performance stock units was $11,001, $8,116 and $7,530, respectively. During fiscal years 2024, 2023 and 2022, the total fair value of other stock awards vested was $8,409, $12,048 and $17,011, respectively. As of December 31, 2024, total unrecognized stock-based compensation expense related to outstanding restricted stock units was $5,865, which will be recognized over a weighted average period of 2.0 years. As of December 31, 2024, total unrecognized stock-based compensation expense related to performance stock units based on our estimated achievement of the established performance criteria was $5,032, which will be recognized over a weighted average period of 1.7 years. The weighted average fair value of market-based performance stock units granted during fiscal year 2024 was $105.35 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 25.3% 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 $607, $451 and $376 of stock-based compensation expense related to our Second Amended and Restated 1997 Employee Stock Purchase Plan (“ESPP”) during fiscal years 2024, 2023 and 2022, respectively. Tax benefit for income taxes associated with stock-based compensation during fiscal years 2024, 2023 and 2022 was $(1,907), $(2,330) and $(1,744), respectively. Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive income (loss), 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, 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, net of tax 12,645 Balance as of December 31, 2022 7,542 Other comprehensive loss before reclassifications (6,843) Amounts reclassified from accumulated other comprehensive income (6,361) Income tax benefit related to items in other comprehensive loss 4,582 Other comprehensive loss, net of tax (8,622) Balance as of December 31, 2023 (1,080) Other comprehensive income before reclassifications 14,631 Amounts reclassified from accumulated other comprehensive loss (8,442) Income tax benefit related to items in other comprehensive income (1,797) Other comprehensive income, net of tax 4,392 Balance as of December 31, 2024 $ 3,312 A summary of reclassifications out of accumulated other comprehensive income (loss), net of tax for fiscal years 2024, 2023 and 2022 is as follows: Fiscal Year Ended 2024 2023 2022 Accumulated Other Comprehensive Income (Loss), Net of Tax Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss), Net of Tax Affected Line Item in the Consolidated Interest rate swaps $ (8,442) $ (6,361) $ 1,443 Interest expense 8,442 6,361 (1,443) Income before income taxes 2,500 2,633 98 Provision for income taxes $ 5,942 $ 3,728 $ (1,541) Net income

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
FAIR VALUE OF FINANCIAL INSTRUMENTS	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, cash equivalents and restricted cash, 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, trade payables and debt. The carrying values of cash, cash equivalents and restricted cash, 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. We recognize all derivatives accounted for on the balance sheet at fair value. See Note 11, 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, 2024 Using: Quoted Prices in Significant Other Significant Assets: Interest rate swaps $ — $ 7,642 $ — Restricted investment securities - landfill closure 2,499 — — $ 2,499 $ 7,642 $ — Liabilities: Interest rate swaps $ — $ 2,852 $ — Fair Value Measurement at December 31, 2023 Using: Quoted Prices in Significant Other Significant Assets: Interest rate swaps $ — $ 10,364 $ — Restricted investment securities - landfill closure 2,203 — — $ 2,203 $ 10,364 $ — Liabilities: Interest rate swaps $ — $ 11,762 $ —

EMPLOYEE BENEFIT PLANS

EMPLOYEE BENEFIT PLANS	12 Months Ended
	Dec. 31, 2024
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 2024, 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 2024, 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 2024, 2023 and 2022 amounted to $5,831, $4,371 and $3,558, respectively. Employee Stock Purchase Plan We offer our eligible employees the opportunity to participate in an employee stock purchase plan. Under the ESPP, qualified employees may purchase shares of Class A common stock by payroll deduction at a 15% discount from the market price. In June 2023, our stockholders approved an amendment and restatement of the ESPP to increase the number of shares of Class A common stock reserved for issuance under the ESPP by 400 shares of Class A common stock. Class A common stock issued under our ESPP during fiscal years 2024, 2023 and 2022 amounted to 30, 24 and 22 shares, respectively. As of December 31, 2024, 377 shares of Class A common stock were available for distribution under our ESPP. Defined Benefit Pension Plan

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES A summary of the provision for income taxes is as follows: Fiscal Year Ended 2024 2023 2022 Federal Current $ 911 $ — $ — Deferred 8,652 8,155 15,645 9,563 8,155 15,645 State Current (297) 4,385 5,362 Deferred (1,754) (894) 880 (2,051) 3,491 6,242 Provision for income taxes $ 7,512 $ 11,646 $ 21,887 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 2024, we assessed the valuation allowance and considered positive evidence, including significant cumulative consolidated income over the three years ended December 31, 2024, revenue growth and expectations of future profitability, and negative evidence, including the impact of significant risks and uncertainties in the business and restrictions on tax loss utilization in certain state jurisdictions. We also considered the impact of acquisitions, including of Whitetail Disposal, Inc. and its integration into the company. After assessing both the positive evidence and the negative evidence, we determined it is more likely than not that certain state deferred tax assets would be realized in the future, and therefore released a portion of the valuation allowance as of December 31, 2024, resulting in a benefit from income taxes of $3,166. As of December 31, 2024, we maintained a valuation allowance of $8,456 primarily related to certain state net operating losses. 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 2024 was a decrease of $2,530. 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 2024 2023 2022 Federal statutory rate 21 % 21 % 21 % Tax at statutory rate $ 4,420 $ 7,779 $ 15,743 State income taxes, net of federal benefit (1,660) 620 4,203 Change in valuation allowance 68 1,675 459 Federal effect of change in state valuation allowance — (312) 282 Expired tax attributes 497 — — Non-deductible officer compensation 1,172 996 1,300 Other non-deductible expenses 2,931 809 782 Deductible stock awards 103 (963) (627) Tax credits 63 (60) (83) Reversal of disproportionate tax effects in other comprehensive (loss) income — 938 — Other, net (82) 164 (172) Provision for income taxes $ 7,512 $ 11,646 $ 21,887 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, 2024 2023 Deferred tax assets: Accrued expenses and reserves $ 60,319 $ 49,339 Net operating loss carryforwards 26,544 35,571 General business and state tax credit carryforwards 3,900 6,862 Interest expense limitation 10,089 6,690 Stock awards 3,256 2,690 Unrealized loss on swaps — 375 Other 1,024 1,567 Total deferred tax assets 105,132 103,094 Less: valuation allowance (8,456) (10,986) Total deferred tax assets after valuation allowance 96,676 92,108 Deferred tax liabilities: Tax over book depreciation of property and equipment (71,467) (58,927) Amortization of intangibles (42,961) (22,540) Unrealized gain on swaps (1,337) — Other — (44) Total deferred tax liabilities (115,765) (81,511) Net deferred tax (liability) asset $ (19,089) $ 10,597 The net deferred tax liability at December 31, 2024 is reflected on the consolidated balance sheet as a long-term deferred federal and state tax liability of $(19,089). As of December 31, 2024, we have, for federal income tax purposes, net operating loss carryforwards of approximately $83,211, which do not expire. We have state net operating loss carryforwards of approximately $125,708 that expire in the fiscal years ending December 31, 2025 through 2044 or that do not expire in certain jurisdictions. In addition, we have $3,900 general business credit carryforwards which expire in the fiscal years ending December 31, 2025 through 2044 and zero state credit carryforwards. 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. 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, 2024 and 2023, 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 2021 through 2024 are open for assessment. Tax years 1999 through 2020 are open for examination to the extent of any NOLs or credits that have been carried forward from those years.

OTHER ITEMS AND CHARGES

OTHER ITEMS AND CHARGES	12 Months Ended
	Dec. 31, 2024
Unusual or Infrequent Items, or Both [Abstract]
OTHER ITEMS AND CHARGES	OTHER ITEMS AND CHARGES Landfill Capping (Recovery) 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 was 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. In fiscal year 2024, we recorded a recovery of $(1,739) consisting of both (i) a partial reversal of historical payments written off after an engineering evaluation determined that a portion of the area affected by the veneer failure was deemed to still be viable as well as (ii) a recovery of operating expenses incurred during the clean up of the affected capping material as part of a settlement with a third party. 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 In the fiscal year ended December 31, 2017, we initiated a plan to cease operations of the Southbridge Landfill and later closed it in November 2018 when the Southbridge Landfill reached its final capacity . Accordingly, in fiscal years 2024, 2023 and 2022, we recorded charges associated with the closure of the Southbridge Landfill as follows: Fiscal Year Ended 2024 2023 2022 Legal and transaction costs (1) $ — $ 412 $ 684 Landfill closure project charge (2) 8,385 55 752 Southbridge Landfill closure charge $ 8,385 $ 467 $ 1,436 (1) We incurred legal costs as well as other transaction costs associated with various matters as part of the Southbridge Landfill closure. (2) Includes a non-cash charge in fiscal year 2024 associated with our receipt of a final closure permit (the “Closure Permit”) from the Massachusetts Department of Environmental Protection related to the Southbridge Landfill. Pursuant to the terms of the Closure Permit, we are required to meet certain general permit conditions and certain specific permit conditions (collectively, the “Conditions”), including environmental monitoring, third-party inspections, inspection of the final cover, leachate sampling, post-closure monitoring, and other post-closure requirements. We have revised the accrued post-closure liability for the Southbridge Landfill to reflect the estimated cost of satisfying the expanded Conditions as currently specified in the Closure Permit. See Note 10, Final Capping, Closure and Post-Closure Costs for disclosure regarding our landfill final capping, closure and post-closure costs. Expense from Acquisition Activities In the fiscal years 2024, 2023 and 2022, we recognized expenses of $24,879, $15,038 and $4,613, respectively, comprised primarily of legal, consulting, rebranding and other costs associated with the due diligence, acquisition and integration of acquired businesses. Fiscal year 2024 includes a charge for an increase in the reserve against accounts receivable of the businesses acquired in the GFL Acquisition as a result of our inability to pursue collections during the transition services period with the seller, resulting in accounts receivable aged beyond what is typical in our business. See Note 6, Accounts Receivable, Net of Allowance for Credit Losses for disclosure over bad debt expense and Note 5, Business Combinations for disclosure regarding acquisition activity. Legal Settlement In fiscal year 2023, we recorded a charge of $6,150 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, which received court approval, was executed on July 24, 2023 and subsequently paid in fiscal year 2024. See Note 12, Commitments and Contingencies for disclosure regarding our aggregate legal proceedings accrual. 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. See Note 12, Commitments and Contingencies for disclosure regarding environmental remediation liabilities.

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE A summary of the numerator and denominators used in the computation of earnings per share is as follows: Fiscal Year Ended 2024 2023 2022 Numerator: Net income $ 13,536 $ 25,399 $ 53,079 Denominator: Class A common stock 62,370 57,007 50,704 Class B common stock 988 988 988 Unvested restricted stock awards — — (1) Effect of weighted average shares outstanding (1) (3,782) (2,821) (68) Basic weighted average common shares outstanding 59,576 55,174 51,623 Impact of potentially dilutive securities: Dilutive effect of stock options and stock awards 105 100 144 Diluted weighted average common shares outstanding 59,681 55,274 51,767 Anti-dilutive potentially issuable shares 25 93 111 (1) Adjustments associated with the timing of 5,175 shares of Class A common stock issued as part of the public offering, completed on September 19, 2024, and 6,053 shares of Class A common stock issued as part of the public offering, completed on June 16, 2023. See Note 13, Stockholders’ Equity for disclosure regarding the public offerings of Class A common stock.

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS	12 Months Ended
	Dec. 31, 2024
Related Party Transactions [Abstract]
RELATED PARTY TRANSACTIONS	RELATED PARTY TRANSACTIONS Services During fiscal years 2024, 2023 and 2022, 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 2024, 2023 and 2022 were $7,762, $7,682 and $12,297, respectively, of which $477 and $595 were outstanding and included in either accounts payable or other current liabilities as of December 31, 2024 and December 31, 2023, respectively. In addition to the total purchased services, we provided various waste collection and disposal services to CCI. Total revenues recorded for fiscal years 2024, 2023 and 2022 were $242, $241 and $141, 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 lease related to our corporate headquarters in Rutland, Vermont has been extended through February 2039 and the lease associated with our Montpelier, Vermont facility has been extended through May 2039. The terms of the lease agreements require monthly payments of approximately $34, subject to a fixed annual escalation. Total expense charged to operations for fiscal years 2024, 2023 and 2022 under these agreements was $554, $284 and $273, 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 2024, 2023 and 2022, we paid $14, $3 and $10, respectively, pursuant to this agreement. As of December 31, 2024 and December 31, 2023, we have accrued $17 and $17, respectively, for costs associated with its post-closure obligations.

SEGMENT REPORTING

SEGMENT REPORTING	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
SEGMENT REPORTING	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. Revenues associated with our solid waste operations are derived mainly from solid waste collection and disposal services, including landfill, transfer station and transportation, while also providing landfill gas-to-energy 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 services provided by 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. Operating income by segment reported in fiscal years 2023 and 2022 have been updated to conform with the presentation for fiscal year 2024, which does not have Corporate Entities costs allocated to our reportable operating segments. See Note 9, Goodwill and Intangible Assets for the breakout of goodwill by reportable operating segment. The accounting policies of our reportable operating segments are the same as those described in Note 3, Summary of Significant Accounting Policies . Our President is our CODM. Our CODM uses operating income in evaluating reportable operating segment performance in order to properly allocate resources and make key operating decisions. Intercompany revenue and expenses are eliminated in the computation of consolidated gross revenues and operating income. The CODM uses operating income for each reportable operating segment in the annual budget and forecasting process and considers budget-to-actual and forecast-to-actual variances on a monthly basis when making decisions about the allocation of operating and capital resources to each reportable operating segment. Summarized financial information concerning our reportable segments for fiscal years 2024, 2023 and 2022, follows: Fiscal Year Ended December 31, 2024: Eastern Western Mid-Atlantic Solid Waste Resource Corporate Eliminations Consolidated Outside revenue $ 416,678 $ 591,214 $ 219,524 $ 1,227,416 $ 329,867 $ — $ — $ 1,557,283 Intercompany revenue 104,529 208,963 2,389 315,881 13,068 — (328,949) — Gross revenue 521,207 800,177 221,913 1,543,297 342,935 — (328,949) 1,557,283 Cost of operations 372,123 545,823 160,993 1,078,939 276,582 764 (328,949) 1,027,336 General and administration 24,101 33,852 13,472 71,425 19,574 99,755 — 190,754 Depreciation and amortization 56,760 105,563 50,636 212,959 18,254 3,694 — 234,907 Expense from acquisition activities 384 3,349 14,815 18,548 105 6,226 — 24,879 Landfill capping (recovery) charge - veneer failure — (1,739) — (1,739) — — — (1,739) Southbridge Landfill closure charge 8,385 — — 8,385 — — — 8,385 Operating income (loss) $ 59,454 $ 113,329 $ (18,003) $ 154,780 $ 28,420 $ (110,439) $ — 72,761 Interest expense, net 51,983 Other income, net (270) Income before income taxes $ 21,048 Interest expense (income), net $ 763 $ 369 $ (6) $ 1,126 $ 117 $ 50,740 $ — $ 51,983 Capital expenditures $ 44,388 $ 100,329 $ 22,873 $ 167,590 $ 25,932 $ 9,705 $ — $ 203,227 Total assets $ 444,295 $ 1,233,688 $ 841,266 $ 2,519,249 $ 256,188 $ 454,631 $ — $ 3,230,068 Fiscal Year Ended December 31, 2023: Eastern Western Mid-Atlantic (1) Solid Waste Resource Corporate Eliminations Consolidated Outside revenue $ 374,463 $ 511,640 $ 85,640 $ 971,743 $ 292,799 $ — $ — $ 1,264,542 Intercompany revenue 92,938 173,044 417 266,399 15,337 — (281,736) — Gross revenue 467,401 684,684 86,057 1,238,142 308,136 — (281,736) 1,264,542 Cost of operations 335,896 458,281 60,294 854,471 259,273 30 (281,736) 832,038 General and administration 24,416 31,672 4,806 60,894 18,149 76,804 — 155,847 Depreciation and amortization 50,881 82,291 20,263 153,435 14,202 3,068 — 170,705 Expense from acquisition activities 352 3,421 5,292 9,065 102 5,871 — 15,038 Legal settlement 2,614 3,536 — 6,150 — — — 6,150 Landfill capping (recovery) charge - veneer failure — 3,870 — 3,870 — — — 3,870 Southbridge Landfill closure charge 467 — — 467 — — — 467 Operating income (loss) $ 52,775 $ 101,613 $ (4,598) $ 149,790 $ 16,410 $ (85,773) $ — 80,427 Interest expense, net 36,837 Other expense, net 6,545 Income before income taxes $ 37,045 Interest expense, net $ 638 $ 380 $ — $ 1,018 $ 143 $ 35,676 $ — $ 36,837 Capital expenditures $ 43,817 $ 82,706 $ 5,271 $ 131,794 $ 14,586 $ 8,527 $ — $ 154,907 Total assets $ 434,323 $ 1,001,090 $ 553,339 $ 1,988,752 $ 253,090 $ 293,628 $ — $ 2,535,470 (1) Operations under the Mid-Atlantic region commenced July 1, 2023. Fiscal Year Ended December 31, 2022: Eastern Western Mid-Atlantic (1) Solid Waste Resource Corporate Eliminations Consolidated Outside revenue $ 340,058 $ 445,153 $ — $ 785,211 $ 299,878 $ — $ — $ 1,085,089 Intercompany revenue 83,201 151,016 — 234,217 5,734 — (239,951) — Gross revenue 423,259 596,169 — 1,019,428 305,612 — (239,951) 1,085,089 Cost of operations 312,446 399,816 — 712,262 250,775 31 (239,951) 723,117 General and administration 21,851 28,105 — 49,956 16,460 67,003 — 133,419 Depreciation and amortization 47,673 64,116 — 111,789 12,082 2,480 — 126,351 Expense from acquisition activities 898 2,335 — 3,233 564 816 — 4,613 Southbridge Landfill closure charge 1,436 — — 1,436 — — — 1,436 Environmental remediation charge — 759 — 759 — — — 759 Operating income (loss) $ 38,955 $ 101,038 $ — $ 139,993 $ 25,731 $ (70,330) $ — 95,394 Interest expense, net 23,013 Other income (2,585) Income before income taxes $ 74,966 Interest expense, net $ 565 $ 508 $ — $ 1,073 $ 146 $ 21,794 $ — $ 23,013 Capital expenditures $ 38,501 $ 65,190 $ — $ 103,691 $ 15,172 $ 12,097 $ — $ 130,960 Total assets $ 372,895 $ 737,658 $ — $ 1,110,553 $ 191,118 $ 147,544 $ — $ 1,449,215 (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 2024 2023 2022 Collection $ 961,784 61.8 % $ 710,590 56.2 % $ 539,587 49.7 % Disposal 246,718 15.8 % 244,582 19.3 % 227,971 21.0 % Landfill gas-to-energy 7,958 0.5 % 6,617 0.5 % 7,519 0.7 % Processing 10,956 0.7 % 9,954 0.8 % 10,134 1.0 % Solid waste operations 1,227,416 78.8 % 971,743 76.8 % 785,211 72.4 % Processing 130,459 8.4 % 105,997 8.4 % 119,045 10.9 % National Accounts 199,408 12.8 % 186,802 14.8 % 180,833 16.7 % Resource Solutions operations 329,867 21.2 % 292,799 23.2 % 299,878 27.6 % Total revenues $ 1,557,283 100.0 % $ 1,264,542 100.0 % $ 1,085,089 100.0 %

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net income	$ 13,536	$ 25,399	$ 53,079

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended	12 Months Ended
	Dec. 31, 2024 shares	Dec. 31, 2024 shares
Trading Arrangements, by Individual
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Paul J. Ligon [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 Paul J. Ligon (Senior Vice President Sustainable Growth) Adoption (12/16/2024) Rule 10b5-1 trading arrangement Sale Through and including 04/01/2026 Up to 4,000 shares
Name	Paul J. Ligon
Title	Senior Vice President Sustainable Growth
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	12/16/2024
Arrangement Duration	471 days
Aggregate Available	4,000	4,000

Insider Trading Policies and Pr

Insider Trading Policies and Procedures	12 Months Ended
	Dec. 31, 2024
Insider Trading Policies and Procedures [Line Items]
Insider Trading Policies and Procedures Adopted	true

Cybersecurity Risk Management a

Cybersecurity Risk Management and Strategy Disclosure	12 Months Ended
	Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	We have specific processes for assessing, identifying and managing cybersecurity risks, which are built into our information technology function and are designed to help protect our information assets and operations from internal and external cyber threats, protect employee and customer information from unauthorized access or attack, as well as secure our networks and systems. These processes are periodically assessed against the National Institute of Standards and Technology cybersecurity framework and include physical, procedural and technical safeguards, response plans, regular tests on our systems, incident simulations and routine review of our policies and procedures to identify risks and refine our practices. The processes are updated as needed on an annual basis. We engage external parties to supplement our internal capabilities and to assess our cyber maturity and readiness on a periodic basis. This includes being party to a managed services agreement with an external party for incident response; engaging an external party for comprehensive cybersecurity assessment, opportunity prioritization, initiative road mapping and cyber project delivery; and engaging additional external parties to assist with critical cyber-related infrastructure such as firewall maintenance and upgrade initiatives. While utilizing third-party service providers presents risk, we assess all third-party service providers for their qualifications before engaging them and monitor such providers throughout the term of the engagement in order to help protect us from any additional vulnerabilities.
Cybersecurity Risk Management Processes Integrated [Flag]	true
Cybersecurity Risk Management Processes Integrated [Text Block]	We have specific processes for assessing, identifying and managing cybersecurity risks, which are built into our information technology function and are designed to help protect our information assets and operations from internal and external cyber threats, protect employee and customer information from unauthorized access or attack, as well as secure our networks and systems. These processes are periodically assessed against the National Institute of Standards and Technology cybersecurity framework and include physical, procedural and technical safeguards, response plans, regular tests on our systems, incident simulations and routine review of our policies and procedures to identify risks and refine our practices. The processes are updated as needed on an annual basis.
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]	false
Cybersecurity Risk Board of Directors Oversight [Text Block]	The Audit Committee of our Board of Directors (“Audit Committee”) provides direct oversight over cybersecurity risk and acts in an advisory capacity to our management team, primarily, as it relates to cybersecurity, our Chief Information Officer (“CIO”), and provides updates to the Board of Directors regarding such oversight. The Audit Committee receives quarterly updates from management regarding cybersecurity matters, and is notified between such updates regarding significant new cybersecurity threats or incidents.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	The Audit Committee of our Board of Directors (“Audit Committee”) provides direct oversight over cybersecurity risk and acts in an advisory capacity to our management team, primarily, as it relates to cybersecurity, our Chief Information Officer (“CIO”), and provides updates to the Board of Directors regarding such oversight
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]	The Audit Committee of our Board of Directors (“Audit Committee”) provides direct oversight over cybersecurity risk and acts in an advisory capacity to our management team, primarily, as it relates to cybersecurity, our Chief Information Officer (“CIO”), and provides updates to the Board of Directors regarding such oversight.
Cybersecurity Risk Role of Management [Text Block]	Our CIO leads the operational oversight of our company-wide cybersecurity strategy, policy, standards and processes and works across relevant departments to assess and help prepare us and our employees to address cybersecurity risks. This includes the utilization of a security operations center which deploys overlapping layers of security technology, monitoring, and staff for incident response. Should an incident arise, we, led by our CIO, follow a documented incident response plan, which includes activating retained third-party incident response specialists. The CIO’s cybersecurity expertise is derived from over 30 years of experience in information technology, consulting, and technology transformation through ever-progressing leadership roles. Our CIO is supported by a dedicated team of cybersecurity professionals in addition to managed services and retained external experts. In an effort to deter and detect cyber threats, we provide key employees with various cybersecurity trainings that cover a range of timely and relevant topics. The trainings function to educate employees on the importance of reporting all incidents immediately. We also use technology-based tools to mitigate cybersecurity risks and to bolster our employee-based cybersecurity programs.
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]	Our CIO leads the operational oversight of our company-wide cybersecurity strategy, policy, standards and processes and works across relevant departments to assess and help prepare us and our employees to address cybersecurity risks.
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	The CIO’s cybersecurity expertise is derived from over 30 years of experience in information technology, consulting, and technology transformation through ever-progressing leadership roles. Our CIO is supported by a dedicated team of cybersecurity professionals in addition to managed services and retained external experts.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]	The Audit Committee receives quarterly updates from management regarding cybersecurity matters, and is notified between such updates regarding significant new cybersecurity threats or incidents.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]	true

ACCOUNTING CHANGES (Policies)

ACCOUNTING CHANGES (Policies)	12 Months Ended
	Dec. 31, 2024
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 ten states: Vermont, New Hampshire, New York, Massachusetts, Connecticut, Maine, Pennsylvania, New Jersey, Delaware and Maryland, with our headquarters located in Rutland, Vermont. 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 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 adopted this guidance effective December 31, 2024 and its adoption had an impact on our reportable operating segment disclosures within our consolidated financial statements and accompanying notes. See Note 20, Segment Reporting for enhanced disclosure. The following table provides a brief description of recent ASUs to the ASC issued by the FASB that are pending adoption as of December 31, 2024 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 Accounting standards issued pending adoption as of December 31, 2024 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. ASU No. 2024-03: Improvements to Income Statement - Expense Disaggregation Disclosures Requires entities to provide additional disclosure related to more detailed information about specific types of expenses contained in commonly presented expense captions on the statements of operations. We are currently assessing the provisions of this guidance and expect that its adoption will have an impact on certain expense category disclosures within our consolidated financial statements and accompanying notes. This guidance is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027.
Management's Estimates and Assumptions	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, asset impairments, if applicable, goodwill recoverability assessment, accounts receivable 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. 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	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	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, 2024, 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, Net of Allowance for Credit Losses
Inventory	Inventory
Property and Equipment	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 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	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 year 2024, the fiscal year ended December 31, 2023 (“fiscal year 2023”) and the fiscal year ended December 31, 2022 (“fiscal year 2022”) was $1,085, $643 and $330, 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 (2.6% as of December 31, 2024). 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, 2024 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 $11,350, $9,529 and $7,565 in fiscal years 2024, 2023 and 2022, 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 17, Other Items and Charges for disclosure about the write-off and subsequent partial recovery 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”) that occurred in fiscal year 2023.
Lease Accounting	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.
Goodwill and Intangible Assets	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.
Investments in Unconsolidated Entities	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, 2024 and December 31, 2023, 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, 2024 and December 31, 2023, 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.
Fair Value of Financial Instruments	Fair Value of Financial Instruments
Business Combinations	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.
Environmental Remediation Liabilities	Environmental Remediation Liabilities
Self-Insurance Liabilities and Related Costs	Self-Insurance Liabilities and Related Costs
Income Taxes	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.
Derivatives and Hedging	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.
Contingent Liabilities	Contingent Liabilities
Revenue Recognition	Revenue Recognition We disaggregate our revenues by applicable service line: collection, landfill, transfer, transportation, landfill gas-to-energy, processing, and services provided by 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 2024, 2023, or 2022 from performance obligations satisfied in previous periods.
Asset Impairments	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 2024. As of October 1, 2024, 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 each case of our Eastern, Western, Mid-Atlantic and Resource Solutions reporting units, the fair value of each reporting unit exceeded its carrying value by in excess of 23%. We incurred no impairment of goodwill as a result of our annual goodwill impairment tests in fiscal years 2024, 2023 or 2022. However, there can be no assurance that goodwill will not be impaired at any time in the future. Cost Method Investments.
Defined Benefit Pension Plan	Defined Benefit Pension Plan
Stock-Based Compensation	Stock-Based Compensation
Earnings per Share	Earnings per Share
Subsequent Events	Subsequent Events We have evaluated subsequent events or transactions that have occurred after the consolidated balance sheet date of December 31, 2024 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, 2024 through the date of this filing that would require recognition or disclosure in our consolidated financial statements.
Fair Value Measurement	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
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. Revenues associated with our solid waste operations are derived mainly from solid waste collection and disposal services, including landfill, transfer station and transportation, while also providing landfill gas-to-energy 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 services provided by 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. Operating income by segment reported in fiscal years 2023 and 2022 have been updated to conform with the presentation for fiscal year 2024, which does not have Corporate Entities costs allocated to our reportable operating segments. See Note 9, Goodwill and Intangible Assets for the breakout of goodwill by reportable operating segment. The accounting policies of our reportable operating segments are the same as those described in Note 3, Summary of Significant Accounting Policies . Our President is our CODM. Our CODM uses operating income in evaluating reportable operating segment performance in order to properly allocate resources and make key operating decisions. Intercompany revenue and expenses are eliminated in the computation of consolidated gross revenues and operating income. The CODM uses operating income for each reportable operating segment in the annual budget and forecasting process and considers budget-to-actual and forecast-to-actual variances on a monthly basis when making decisions about the allocation of operating and capital resources to each reportable operating segment.

ACCOUNTING CHANGES (Tables)

ACCOUNTING CHANGES (Tables)	12 Months Ended
	Dec. 31, 2024
Accounting Changes and Error Corrections [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	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 in the fiscal year ended December 31, 2024 (“fiscal year 2024”): Standard Description Effect on the Financial Statements or Other 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 adopted this guidance effective December 31, 2024 and its adoption had an impact on our reportable operating segment disclosures within our consolidated financial statements and accompanying notes. See Note 20, Segment Reporting for enhanced disclosure. The following table provides a brief description of recent ASUs to the ASC issued by the FASB that are pending adoption as of December 31, 2024 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 Accounting standards issued pending adoption as of December 31, 2024 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. ASU No. 2024-03: Improvements to Income Statement - Expense Disaggregation Disclosures Requires entities to provide additional disclosure related to more detailed information about specific types of expenses contained in commonly presented expense captions on the statements of operations. We are currently assessing the provisions of this guidance and expect that its adoption will have an impact on certain expense category disclosures within our consolidated financial statements and accompanying notes. This guidance is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2024
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 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, 2024 2023 Land $ 56,010 $ 47,863 Landfills 859,602 786,130 Finance lease right-of-use assets 128,159 101,770 Buildings and improvements 303,170 262,204 Machinery and equipment 318,391 287,175 Rolling stock 490,571 396,247 Containers 311,236 266,705 Total property and equipment (1) 2,467,139 2,148,094 Less: accumulated depreciation and amortization (1,302,324) (1,167,541) Property and equipment, net $ 1,164,815 $ 980,553 (1) Includes construction-in-process of $104,686 and $74,408 at December 31, 2024 and December 31, 2023, respectively, that have not been placed in service and, therefore, have not begun depreciating.

REVENUE RECOGNITION (Tables)

REVENUE RECOGNITION (Tables)	12 Months Ended
	Dec. 31, 2024
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, 2024 Eastern Western Mid-Atlantic Resource Solutions Total Revenues Collection $ 302,585 $ 441,386 $ 217,813 $ — $ 961,784 Landfill 30,541 64,204 — — 94,745 Transfer station 68,229 61,430 1,711 — 131,370 Transportation 5,298 15,305 — — 20,603 Landfill gas-to-energy 1,661 6,297 — — 7,958 Processing 8,364 2,592 — 130,459 141,415 National Accounts — — — 199,408 199,408 Total revenues $ 416,678 $ 591,214 $ 219,524 $ 329,867 $ 1,557,283 Transferred at a point-in-time $ 471 $ 2,516 $ — $ 58,273 $ 61,260 Transferred over time 416,207 588,698 219,524 271,594 1,496,023 Total revenues $ 416,678 $ 591,214 $ 219,524 $ 329,867 $ 1,557,283 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 station 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 station 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.

BUSINESS COMBINATIONS (Tables)

BUSINESS COMBINATIONS (Tables)	12 Months Ended
	Dec. 31, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [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 2024 2023 2022 Purchase Price: Cash used in acquisitions, net of cash acquired of $11,687, $1,014, and $—, respectively $ 469,159 $ 846,711 $ 76,573 Other non-cash consideration — — 1,275 Working capital settlements due from sellers (2,987) (2,873) — Holdbacks and additional consideration due to sellers 1,689 2,729 4,840 Total consideration 467,861 846,567 82,688 Allocated as follows: Current assets (1) 15,992 19,524 7,644 Property and equipment: Land 7,026 8,440 3,141 Buildings and improvements 9,878 28,411 8,576 Machinery, equipment and other 89,995 177,916 11,689 Operating lease right-of-use assets 5,222 11,786 405 Intangible assets: Trade names 12,470 4,320 55 Covenants not-to-compete 10,997 30,860 2,424 Customer relationships 104,762 145,393 12,224 Other non-current assets — — 40 Deferred tax liability (20,392) (9,058) — Current liabilities (27,755) (21,417) (3,812) Other long-term liabilities — (828) (123) Operating lease liabilities, less current portion (5,092) (9,939) (282) Fair value of assets acquired and liabilities assumed 203,103 385,408 41,981 Excess purchase price to be allocated to goodwill $ 264,758 $ 461,159 $ 40,707 (1) Includes contract receivables in fiscal year 2024, 2023 and 2022 of $12,936, $17,002 and $6,806, respectively. Substantially all of contractual amounts are expected to be collected.
Schedule of Unaudited Pro forma Combined Information	Unaudited pro forma combined information that shows our operational results as though each acquisition completed through December 31, 2024 had occurred as of January 1, 2022 is as follows: Fiscal Year Ended 2024 2023 2022 Revenues $ 1,699,991 $ 1,653,535 $ 1,629,041 Operating income $ 66,320 $ 79,815 $ 104,422 Net income $ 8,784 $ 21,111 $ 52,726 Basic earnings per share attributable to common stockholders: Basic weighted average shares outstanding 59,576 55,174 51,623 Basic earnings per common share $ 0.15 $ 0.38 $ 1.02 Diluted earnings per share attributable to common stockholders: Diluted weighted average shares outstanding 59,681 55,274 51,767 Diluted earnings per common share $ 0.15 $ 0.38 $ 1.02

ACCOUNTS RECEIVABLE, NET OF A_2

ACCOUNTS RECEIVABLE, NET OF ALLOWANCE FOR CREDIT LOSSES (Tables)	12 Months Ended
	Dec. 31, 2024
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 2024 2023 2022 Balance at beginning of period $ 4,066 $ 3,016 $ 3,276 Additions - charged to expense (1) 5,987 2,468 1,893 Additions - reserve for acquired receivables with credit deterioration 870 — — Deductions - write offs charged against the allowance, net of recoveries (2,408) (1,418) (2,153) Balance at end of period $ 8,515 $ 4,066 $ 3,016 (1) Includes a charge recorded in fiscal year 2024 in expense from acquisition activities for an increase in the reserve against accounts receivable of the businesses acquired in the GFL Acquisition as a result of our inability to pursue collections during the transition services period with the seller, resulting in accounts receivable aged beyond what is typical in our business. See Note 17, Other Items and Charges for disclosure regarding expense from acquisition activities.

PROPERTY AND EQUIPMENT (Tables)

PROPERTY AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2024
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 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, 2024 2023 Land $ 56,010 $ 47,863 Landfills 859,602 786,130 Finance lease right-of-use assets 128,159 101,770 Buildings and improvements 303,170 262,204 Machinery and equipment 318,391 287,175 Rolling stock 490,571 396,247 Containers 311,236 266,705 Total property and equipment (1) 2,467,139 2,148,094 Less: accumulated depreciation and amortization (1,302,324) (1,167,541) Property and equipment, net $ 1,164,815 $ 980,553 (1) Includes construction-in-process of $104,686 and $74,408 at December 31, 2024 and December 31, 2023, respectively, that have not been placed in service and, therefore, have not begun depreciating.

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2024
Leases [Abstract]
Schedule of Lease Costs and Other Lease Information	A schedule of lease costs and other lease information follows: Fiscal Year Ended 2024 2023 Lease cost: Amortization of right-of-use assets $ 9,216 $ 7,383 Interest expense 2,594 1,840 Fixed lease cost - vehicles, equipment and property 8,021 6,292 Fixed lease cost - landfill operating leases 9,763 9,026 Fixed lease cost 17,784 15,318 Short-term lease cost 9,603 5,313 Variable lease cost 780 604 Total lease cost $ 39,977 $ 30,458 Other information: Cash paid for amounts included in the measurement of lease liabilities: Financing cash flows for finance leases $ 12,071 $ 8,981 Operating cash flows for operating leases $ 11,884 $ 10,578 Right-of-use assets obtained in exchange for new finance lease liabilities $ 28,723 $ 12,211 Right-of-use assets obtained in exchange for new operating lease liabilities $ 11,686 $ 19,796 December 31, 2024 Weighted-average remaining lease term - finance leases (years) 5.1 Weighted-average remaining lease term - operating leases (years) 9.9 Weighted-average discount rate - finance leases 4.6 % Weighted-average discount rate - operating leases 4.8 %
Schedule of Estimated Minimum Future Finance Lease Obligations	Estimated minimum future lease obligations as of December 31, 2024 for each of the next five fiscal years and thereafter are as follows: Operating Leases Finance Leases Fiscal year ending December 31, 2025 $ 13,608 $ 19,951 Fiscal year ending December 31, 2026 12,719 15,367 Fiscal year ending December 31, 2027 11,669 11,399 Fiscal year ending December 31, 2028 8,926 10,750 Fiscal year ending December 31, 2029 8,656 8,571 Thereafter 40,069 14,366 Total lease payments 95,647 80,404 Less: interest (20,907) (10,742) Lease liability balance $ 74,740 $ 69,662
Schedule of Estimated Minimum Future Operating Lease Obligations	Estimated minimum future lease obligations as of December 31, 2024 for each of the next five fiscal years and thereafter are as follows: Operating Leases Finance Leases Fiscal year ending December 31, 2025 $ 13,608 $ 19,951 Fiscal year ending December 31, 2026 12,719 15,367 Fiscal year ending December 31, 2027 11,669 11,399 Fiscal year ending December 31, 2028 8,926 10,750 Fiscal year ending December 31, 2029 8,656 8,571 Thereafter 40,069 14,366 Total lease payments 95,647 80,404 Less: interest (20,907) (10,742) Lease liability balance $ 74,740 $ 69,662

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill Activity	A summary of the activity and balances related to goodwill by reportable operating segment is as follows: December 31, 2023 Acquisitions Business Combination Adjustments December 31, 2024 Eastern $ 73,893 $ 774 $ — $ 74,667 Western 285,056 92,825 704 378,585 Mid-Atlantic 332,247 171,159 946 504,352 Resource Solutions 44,474 — 188 44,662 Total $ 735,670 $ 264,758 $ 1,838 $ 1,002,266 December 31, 2022 Acquisitions Business Combination 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
Schedule of Intangible Assets by Type	A summary of intangible assets is as follows: Covenants Customer Relationships Trade Names Total Balance, December 31, 2024 Intangible assets $ 71,568 $ 377,600 $ 25,795 $ 474,963 Less accumulated amortization (34,398) (115,305) (11,792) (161,495) $ 37,170 $ 262,295 $ 14,003 $ 313,468 Covenants Customer Relationships Trade Names Total Balance, December 31, 2023 Intangible assets $ 61,573 $ 272,571 $ 13,325 $ 347,469 Less accumulated amortization (26,645) (72,227) (7,168) (106,040) $ 34,928 $ 200,344 $ 6,157 $ 241,429
Schedule of Intangible Amortization Expense Estimated	Based on the amortizable intangible assets recorded in the consolidated balance sheets at December 31, 2024, intangible amortization expense for each of the next five fiscal years and thereafter is estimated as follows: Fiscal year ending December 31, 2025 $ 67,846 Fiscal year ending December 31, 2026 $ 60,006 Fiscal year ending December 31, 2027 $ 52,478 Fiscal year ending December 31, 2028 $ 44,749 Fiscal year ending December 31, 2029 $ 34,086 Thereafter $ 54,303

FINAL CAPPING, CLOSURE AND PO_2

FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS (Tables)	12 Months Ended
	Dec. 31, 2024
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 2024 2023 Beginning balance $ 133,904 $ 113,678 Obligations incurred 7,093 5,447 Revisions in estimates (1) 29,537 14,030 Accretion expense 11,350 9,529 Obligations settled (2) (8,765) (11,801) (Recovery) write-off of capping payments (3) (889) 3,021 Ending balance $ 172,230 $ 133,904 (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. Fiscal year 2024 includes $8,385 related to the revision in estimates of the post-closure liability for the Town of Southbridge, Massachusetts landfill (“Southbridge Landfill”), related to the final closure permit. See Note 17, Other Items and Charges for further disclosure over the Southbridge Landfill revision. (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 historical payments associated with capping work that was deemed no longer viable due to a veneer failure at the Ontario County Landfill, which we operate, that occurred in fiscal year 2023, and subsequent partial recovery in fiscal year 2024 after an engineering evaluation determined that a portion of the affected area was still viable. See Note 17, Other Items and Charges for additional disclosure.

DEBT (Tables)

DEBT (Tables)	12 Months Ended
	Dec. 31, 2024
Debt And Derivatives Disclosure [Abstract]
Schedule of Debt	A summary of debt is as follows: December 31, 2024 2023 Senior Secured Credit Facility: Term loan A facility (“Term Loan Facility”) payable quarterly beginning in the fiscal year ended December 31, 2027 with balance due September 2029; bearing interest at 5.967% as of December 31, 2024 $ 800,000 $ — Term loan A facility payable quarterly with balance due December 2026 amended and restated in September 2024 as the Term Loan Facility — 350,000 Term loan A facility payable quarterly with balance due December 2026 amended and restated in September 2024 as the Term Loan Facility — 419,250 Revolving credit facility (“Revolving Credit Facility”) due September 2029; bearing interest at term secured overnight financing rate (“Term SOFR”) plus 1.610% — — Revolving credit facility due December 2026 amended and restated in September 2024 as the Revolving Credit Facility — — 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 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 Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2024 (“FAME Bonds 2024”) due December 2047 - fixed rate interest period bearing interest at 4.625% through May 2035 45,000 — 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 69,662 53,066 Notes payable maturing through September 2028; bearing interest up to 8.1% 1,500 230 Principal amount of debt 1,148,162 1,054,546 Less—unamortized debt issuance costs 14,911 11,103 Debt less unamortized debt issuance costs 1,133,251 1,043,443 Less—current maturities of debt 42,619 35,781 Debt, less current portion $ 1,090,632 $ 1,007,662 Term SOFR Loans Base Rate Loans Credit Facility 1.300% to 2.175% 0.300% to 1.175%
Schedule of Components of Interest Expense	The components of interest expense are as follows: Fiscal Year Ended 2024 2023 2022 Interest expense on long-term debt and finance leases $ 60,077 $ 44,836 $ 21,691 Amortization of debt issuance costs (1) 2,960 2,962 1,903 Letter of credit fees 459 423 458 Less: capitalized interest (1,085) (643) (330) Total interest expense $ 62,411 $ 47,578 $ 23,722 (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 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, 2022 $ 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 515,000 — 515,000 Additions — — — Commencements — — — Maturities — — — Balance, December 31, 2024 (1) $ 515,000 $ — $ 515,000 (1) 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, December 31, Interest rate swaps Other current assets $ 3,606 $ 5,951 Interest rate swaps Other non-current assets 4,036 4,413 Total $ 7,642 $ 10,364 Interest rate swaps Other accrued liabilities $ 570 $ — Interest rate swaps Other long-term liabilities 2,282 11,762 Total $ 2,852 $ 11,762 Interest rate swaps Accumulated other comprehensive income (loss), net $ 4,790 $ (1,398) Interest rate swaps - tax effect Accumulated other comprehensive income (loss), net (1,478) 318 $ 3,312 $ (1,080)
Schedule of Future Maturities of Debt	Aggregate principal maturities of debt as of December 31, 2024 for each of the next five fiscal years and thereafter are as follows: Fiscal year ending December 31, 2025 $ 42,619 Fiscal year ending December 31, 2026 13,717 Fiscal year ending December 31, 2027 18,201 Fiscal year ending December 31, 2028 29,968 Fiscal year ending December 31, 2029 790,815 Thereafter 252,842 $ 1,148,162

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Schedule of Environmental Liability	A summary of the changes to the aggregate environmental remediation liabilities for the twelve months ended December 31, 2024 and 2023 follows: Twelve Months Ended 2024 2023 Beginning balance $ 5,889 $ 6,335 Accretion expense 95 100 Obligations settled (2) (452) (546) Ending balance 5,532 5,889 Less: current portion 1,597 1,662 Long-term portion $ 3,935 $ 4,227 (1) 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, 2024 for each of the next five fiscal years and thereafter are as follows: Fiscal year ending December 31, 2025 $ 1,599 Fiscal year ending December 31, 2026 281 Fiscal year ending December 31, 2027 278 Fiscal year ending December 31, 2028 304 Fiscal year ending December 31, 2029 297 Thereafter 3,406 Total $ 6,165
Schedule of Reconciliation of Expected Aggregate Non-inflated, Undiscounted Environmental Remediation Liability to Amount Recognized in Statement of Financial Position	A reconciliation of the expected aggregate non-inflated, undiscounted environmental remediation liabilities to the amount recognized in our consolidated balance sheet at December 31, 2024 is as follows: Undiscounted liability $ 6,165 Less discount, net (633) Liability balance - December 31, 2024 $ 5,532
Schedule of Cash and Cash Equivalents	A reconciliation of cash, cash equivalents and restricted cash is as follows: December 31, 2024 December 31, 2023 Cash and cash equivalents $ 358,303 $ 220,912 Restricted cash 25,000 — Cash, cash equivalents and restricted cash $ 383,303 $ 220,912
Schedule of Restricted Cash	A reconciliation of cash, cash equivalents and restricted cash is as follows: December 31, 2024 December 31, 2023 Cash and cash equivalents $ 358,303 $ 220,912 Restricted cash 25,000 — Cash, cash equivalents and restricted cash $ 383,303 $ 220,912

STOCKHOLDERS' EQUITY (Tables)

STOCKHOLDERS' EQUITY (Tables)	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Schedule of Stock Option Activity	A summary of stock option activity is as follows: Stock Options Weighted Weighted Aggregate Outstanding, December 31, 2023 129 $ 66.03 Granted — $ — Exercised (28) $ 12.48 Forfeited or expired — $ — Outstanding, December 31, 2024 101 $ 80.85 7.7 $ 2,518 Exercisable, December 31, 2024 42 $ 79.50 7.5 $ 1,102
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 Weighted Average Aggregate Intrinsic Outstanding, December 31, 2023 181 $ 84.82 Granted 106 $ 99.61 Class A common stock vested (84) $ 88.60 Forfeited or canceled (6) $ 85.70 Outstanding, December 31, 2024 197 $ 91.14 1.9 $ 20,882 Unvested, December 31, 2024 327 $ 92.55 1.7 $ 34,625 (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 130 shares of Class A common stock currently included in unvested. The market-based performance stock unit grants that vested in fiscal year 2024 resulted in the issuance of 38 additional shares of Class A common stock.
Schedule of Changes in Balances of Each Component of Accumulated Other Comprehensive Income (Loss), Net of Tax	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, 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, net of tax 12,645 Balance as of December 31, 2022 7,542 Other comprehensive loss before reclassifications (6,843) Amounts reclassified from accumulated other comprehensive income (6,361) Income tax benefit related to items in other comprehensive loss 4,582 Other comprehensive loss, net of tax (8,622) Balance as of December 31, 2023 (1,080) Other comprehensive income before reclassifications 14,631 Amounts reclassified from accumulated other comprehensive loss (8,442) Income tax benefit related to items in other comprehensive income (1,797) Other comprehensive income, net of tax 4,392 Balance as of December 31, 2024 $ 3,312
Schedule of Reclassifications Out of Accumulated Other Comprehensive Loss, Net of Tax	A summary of reclassifications out of accumulated other comprehensive income (loss), net of tax for fiscal years 2024, 2023 and 2022 is as follows: Fiscal Year Ended 2024 2023 2022 Accumulated Other Comprehensive Income (Loss), Net of Tax Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss), Net of Tax Affected Line Item in the Consolidated Interest rate swaps $ (8,442) $ (6,361) $ 1,443 Interest expense 8,442 6,361 (1,443) Income before income taxes 2,500 2,633 98 Provision for income taxes $ 5,942 $ 3,728 $ (1,541) Net income

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Measured at Fair Value	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, 2024 Using: Quoted Prices in Significant Other Significant Assets: Interest rate swaps $ — $ 7,642 $ — Restricted investment securities - landfill closure 2,499 — — $ 2,499 $ 7,642 $ — Liabilities: Interest rate swaps $ — $ 2,852 $ — Fair Value Measurement at December 31, 2023 Using: Quoted Prices in Significant Other Significant Assets: Interest rate swaps $ — $ 10,364 $ — Restricted investment securities - landfill closure 2,203 — — $ 2,203 $ 10,364 $ — Liabilities: Interest rate swaps $ — $ 11,762 $ —

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Schedule of Benefit for Income Taxes	A summary of the provision for income taxes is as follows: Fiscal Year Ended 2024 2023 2022 Federal Current $ 911 $ — $ — Deferred 8,652 8,155 15,645 9,563 8,155 15,645 State Current (297) 4,385 5,362 Deferred (1,754) (894) 880 (2,051) 3,491 6,242 Provision for income taxes $ 7,512 $ 11,646 $ 21,887
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 2024 2023 2022 Federal statutory rate 21 % 21 % 21 % Tax at statutory rate $ 4,420 $ 7,779 $ 15,743 State income taxes, net of federal benefit (1,660) 620 4,203 Change in valuation allowance 68 1,675 459 Federal effect of change in state valuation allowance — (312) 282 Expired tax attributes 497 — — Non-deductible officer compensation 1,172 996 1,300 Other non-deductible expenses 2,931 809 782 Deductible stock awards 103 (963) (627) Tax credits 63 (60) (83) Reversal of disproportionate tax effects in other comprehensive (loss) income — 938 — Other, net (82) 164 (172) Provision for income taxes $ 7,512 $ 11,646 $ 21,887
Schedule of Deferred Tax Assets and Liabilities	A summary of deferred tax assets and liabilities is as follows: December 31, 2024 2023 Deferred tax assets: Accrued expenses and reserves $ 60,319 $ 49,339 Net operating loss carryforwards 26,544 35,571 General business and state tax credit carryforwards 3,900 6,862 Interest expense limitation 10,089 6,690 Stock awards 3,256 2,690 Unrealized loss on swaps — 375 Other 1,024 1,567 Total deferred tax assets 105,132 103,094 Less: valuation allowance (8,456) (10,986) Total deferred tax assets after valuation allowance 96,676 92,108 Deferred tax liabilities: Tax over book depreciation of property and equipment (71,467) (58,927) Amortization of intangibles (42,961) (22,540) Unrealized gain on swaps (1,337) — Other — (44) Total deferred tax liabilities (115,765) (81,511) Net deferred tax (liability) asset $ (19,089) $ 10,597

OTHER ITEMS AND CHARGES (Tables

OTHER ITEMS AND CHARGES (Tables)	12 Months Ended
	Dec. 31, 2024
Unusual or Infrequent Items, or Both [Abstract]
Schedule of Southbridge Landfill Closure Charge, Net	Accordingly, in fiscal years 2024, 2023 and 2022, we recorded charges associated with the closure of the Southbridge Landfill as follows: Fiscal Year Ended 2024 2023 2022 Legal and transaction costs (1) $ — $ 412 $ 684 Landfill closure project charge (2) 8,385 55 752 Southbridge Landfill closure charge $ 8,385 $ 467 $ 1,436 (1) We incurred legal costs as well as other transaction costs associated with various matters as part of the Southbridge Landfill closure. (2) Includes a non-cash charge in fiscal year 2024 associated with our receipt of a final closure permit (the “Closure Permit”) from the Massachusetts Department of Environmental Protection related to the Southbridge Landfill. Pursuant to the terms of the Closure Permit, we are required to meet certain general permit conditions and certain specific permit conditions (collectively, the “Conditions”), including environmental monitoring, third-party inspections, inspection of the final cover, leachate sampling, post-closure monitoring, and other post-closure requirements. We have revised the accrued post-closure liability for the Southbridge Landfill to reflect the estimated cost of satisfying the expanded Conditions as currently specified in the Closure Permit. See Note 10, Final Capping, Closure and Post-Closure Costs for disclosure regarding our landfill final capping, closure and post-closure costs.

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Schedule of Earnings per Share Computation	A summary of the numerator and denominators used in the computation of earnings per share is as follows: Fiscal Year Ended 2024 2023 2022 Numerator: Net income $ 13,536 $ 25,399 $ 53,079 Denominator: Class A common stock 62,370 57,007 50,704 Class B common stock 988 988 988 Unvested restricted stock awards — — (1) Effect of weighted average shares outstanding (1) (3,782) (2,821) (68) Basic weighted average common shares outstanding 59,576 55,174 51,623 Impact of potentially dilutive securities: Dilutive effect of stock options and stock awards 105 100 144 Diluted weighted average common shares outstanding 59,681 55,274 51,767 Anti-dilutive potentially issuable shares 25 93 111 (1) Adjustments associated with the timing of 5,175 shares of Class A common stock issued as part of the public offering, completed on September 19, 2024, and 6,053 shares of Class A common stock issued as part of the public offering, completed on June 16, 2023. See Note 13, Stockholders’ Equity for disclosure regarding the public offerings of Class A common stock.

SEGMENT REPORTING (Tables)

SEGMENT REPORTING (Tables)	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Schedule of Segment Reporting Information by Segment	Summarized financial information concerning our reportable segments for fiscal years 2024, 2023 and 2022, follows: Fiscal Year Ended December 31, 2024: Eastern Western Mid-Atlantic Solid Waste Resource Corporate Eliminations Consolidated Outside revenue $ 416,678 $ 591,214 $ 219,524 $ 1,227,416 $ 329,867 $ — $ — $ 1,557,283 Intercompany revenue 104,529 208,963 2,389 315,881 13,068 — (328,949) — Gross revenue 521,207 800,177 221,913 1,543,297 342,935 — (328,949) 1,557,283 Cost of operations 372,123 545,823 160,993 1,078,939 276,582 764 (328,949) 1,027,336 General and administration 24,101 33,852 13,472 71,425 19,574 99,755 — 190,754 Depreciation and amortization 56,760 105,563 50,636 212,959 18,254 3,694 — 234,907 Expense from acquisition activities 384 3,349 14,815 18,548 105 6,226 — 24,879 Landfill capping (recovery) charge - veneer failure — (1,739) — (1,739) — — — (1,739) Southbridge Landfill closure charge 8,385 — — 8,385 — — — 8,385 Operating income (loss) $ 59,454 $ 113,329 $ (18,003) $ 154,780 $ 28,420 $ (110,439) $ — 72,761 Interest expense, net 51,983 Other income, net (270) Income before income taxes $ 21,048 Interest expense (income), net $ 763 $ 369 $ (6) $ 1,126 $ 117 $ 50,740 $ — $ 51,983 Capital expenditures $ 44,388 $ 100,329 $ 22,873 $ 167,590 $ 25,932 $ 9,705 $ — $ 203,227 Total assets $ 444,295 $ 1,233,688 $ 841,266 $ 2,519,249 $ 256,188 $ 454,631 $ — $ 3,230,068 Fiscal Year Ended December 31, 2023: Eastern Western Mid-Atlantic (1) Solid Waste Resource Corporate Eliminations Consolidated Outside revenue $ 374,463 $ 511,640 $ 85,640 $ 971,743 $ 292,799 $ — $ — $ 1,264,542 Intercompany revenue 92,938 173,044 417 266,399 15,337 — (281,736) — Gross revenue 467,401 684,684 86,057 1,238,142 308,136 — (281,736) 1,264,542 Cost of operations 335,896 458,281 60,294 854,471 259,273 30 (281,736) 832,038 General and administration 24,416 31,672 4,806 60,894 18,149 76,804 — 155,847 Depreciation and amortization 50,881 82,291 20,263 153,435 14,202 3,068 — 170,705 Expense from acquisition activities 352 3,421 5,292 9,065 102 5,871 — 15,038 Legal settlement 2,614 3,536 — 6,150 — — — 6,150 Landfill capping (recovery) charge - veneer failure — 3,870 — 3,870 — — — 3,870 Southbridge Landfill closure charge 467 — — 467 — — — 467 Operating income (loss) $ 52,775 $ 101,613 $ (4,598) $ 149,790 $ 16,410 $ (85,773) $ — 80,427 Interest expense, net 36,837 Other expense, net 6,545 Income before income taxes $ 37,045 Interest expense, net $ 638 $ 380 $ — $ 1,018 $ 143 $ 35,676 $ — $ 36,837 Capital expenditures $ 43,817 $ 82,706 $ 5,271 $ 131,794 $ 14,586 $ 8,527 $ — $ 154,907 Total assets $ 434,323 $ 1,001,090 $ 553,339 $ 1,988,752 $ 253,090 $ 293,628 $ — $ 2,535,470 (1) Operations under the Mid-Atlantic region commenced July 1, 2023. Fiscal Year Ended December 31, 2022: Eastern Western Mid-Atlantic (1) Solid Waste Resource Corporate Eliminations Consolidated Outside revenue $ 340,058 $ 445,153 $ — $ 785,211 $ 299,878 $ — $ — $ 1,085,089 Intercompany revenue 83,201 151,016 — 234,217 5,734 — (239,951) — Gross revenue 423,259 596,169 — 1,019,428 305,612 — (239,951) 1,085,089 Cost of operations 312,446 399,816 — 712,262 250,775 31 (239,951) 723,117 General and administration 21,851 28,105 — 49,956 16,460 67,003 — 133,419 Depreciation and amortization 47,673 64,116 — 111,789 12,082 2,480 — 126,351 Expense from acquisition activities 898 2,335 — 3,233 564 816 — 4,613 Southbridge Landfill closure charge 1,436 — — 1,436 — — — 1,436 Environmental remediation charge — 759 — 759 — — — 759 Operating income (loss) $ 38,955 $ 101,038 $ — $ 139,993 $ 25,731 $ (70,330) $ — 95,394 Interest expense, net 23,013 Other income (2,585) Income before income taxes $ 74,966 Interest expense, net $ 565 $ 508 $ — $ 1,073 $ 146 $ 21,794 $ — $ 23,013 Capital expenditures $ 38,501 $ 65,190 $ — $ 103,691 $ 15,172 $ 12,097 $ — $ 130,960 Total assets $ 372,895 $ 737,658 $ — $ 1,110,553 $ 191,118 $ 147,544 $ — $ 1,449,215 (1) Operations under the Mid-Atlantic region commenced July 1, 2023.
Schedule of Revenue Attributable to Services	Amount of our total revenue attributable to services provided are as follows: Fiscal Year Ended 2024 2023 2022 Collection $ 961,784 61.8 % $ 710,590 56.2 % $ 539,587 49.7 % Disposal 246,718 15.8 % 244,582 19.3 % 227,971 21.0 % Landfill gas-to-energy 7,958 0.5 % 6,617 0.5 % 7,519 0.7 % Processing 10,956 0.7 % 9,954 0.8 % 10,134 1.0 % Solid waste operations 1,227,416 78.8 % 971,743 76.8 % 785,211 72.4 % Processing 130,459 8.4 % 105,997 8.4 % 119,045 10.9 % National Accounts 199,408 12.8 % 186,802 14.8 % 180,833 16.7 % Resource Solutions operations 329,867 21.2 % 292,799 23.2 % 299,878 27.6 % Total revenues $ 1,557,283 100.0 % $ 1,264,542 100.0 % $ 1,085,089 100.0 %

BASIS OF PRESENTATION (Details)

BASIS OF PRESENTATION (Details)	12 Months Ended
	Dec. 31, 2024 state segment
Segment Reporting Information [Line Items]
Number of states in which entity operates | state	10
Solid Waste Operations
Segment Reporting Information [Line Items]
Number of operating segments | segment	3

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Estimated Useful Lives of Assets (Details)	Dec. 31, 2024
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

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Landfill and Lease Accounting (Details)	12 Months Ended
	Dec. 31, 2024 USD ($) agreement	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Property, Plant and Equipment [Line Items]
Capitalized interest	$ 1,085,000	$ 643,000	$ 330,000
Closure and post-closure costs incurrence period	30 years
Estimate of inflation rate	2.60%
Accretion expense	$ 11,350,000	9,529,000
Number of operation and management agreements entered into | agreement	3
Closure and post closure costs
Property, Plant and Equipment [Line Items]
Accretion expense	$ 11,350,000	9,529,000	$ 7,565,000
Surety bond	266,446,000	241,728,000
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%

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Intangible Assets and Investments in Unconsolidated Entities (Details) - USD ($)	Dec. 31, 2024	Dec. 31, 2023
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

SUMMARY OF SIGNIFICANT ACCOUN_6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Self-Insurance Liabilities and Related Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Capital Leased Assets [Line Items]
Maximum exposure per individual event	$ 1,500
Self insurance reserves	24,949	$ 22,427
Automobile Plan | Minimum
Capital Leased Assets [Line Items]
Potential exposure per individual event	2,000
Automobile Plan | Maximum
Capital Leased Assets [Line Items]
Potential exposure per individual event	$ 4,200

SUMMARY OF SIGNIFICANT ACCOUN_7

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES -Revenue Recognition (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Gross receivables from contracts	$ 162,916	$ 158,931
Contract liabilities	$ 50,690	$ 31,472

SUMMARY OF SIGNIFICANT ACCOUN_8

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Asset Impairments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Goodwill impairment incurred	$ 0	$ 0	$ 0
Cost method investments, impairment incurred	$ 0	$ 0	$ 0
Mid-Atlantic
Segment Reporting Information [Line Items]
Percentage of fair value in excess of carrying amount	23%

SUMMARY OF SIGNIFICANT ACCOUN_9

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Defined Benefit Pension Plan (Details)	12 Months Ended
	Dec. 31, 2024 plan
Pension Plan
Multiemployer Plans [Line Items]
Number of plans	1

REVENUE RECOGNITION (Details)

REVENUE RECOGNITION (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,557,283	$ 1,264,542	$ 1,085,089
Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	61,260	37,848	55,335
Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	1,496,023	1,226,694	1,029,754
Eastern
Disaggregation of Revenue [Line Items]
Total revenues	416,678	374,463	340,058
Eastern | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	471	463	462
Eastern | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	416,207	374,000	339,596
Western
Disaggregation of Revenue [Line Items]
Total revenues	591,214	511,640	445,153
Western | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	2,516	2,731	2,138
Western | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	588,698	508,909	443,015
Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	219,524	85,640	0
Mid-Atlantic | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Mid-Atlantic | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	219,524	85,640	0
Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	329,867	292,799	299,878
Resource Solutions | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	58,273	34,654	52,735
Resource Solutions | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	271,594	258,145	247,143
Collection
Disaggregation of Revenue [Line Items]
Total revenues	961,784	710,590	539,587
Collection | Eastern
Disaggregation of Revenue [Line Items]
Total revenues	302,585	266,991	233,043
Collection | Western
Disaggregation of Revenue [Line Items]
Total revenues	441,386	358,883	306,544
Collection | Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	217,813	84,716	0
Collection | Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Landfill
Disaggregation of Revenue [Line Items]
Total revenues	94,745	101,001	97,542
Landfill | Eastern
Disaggregation of Revenue [Line Items]
Total revenues	30,541	28,275	27,301
Landfill | Western
Disaggregation of Revenue [Line Items]
Total revenues	64,204	72,726	70,241
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 station
Disaggregation of Revenue [Line Items]
Total revenues	131,370	122,955	110,562
Transfer station | Eastern
Disaggregation of Revenue [Line Items]
Total revenues	68,229	65,401	65,800
Transfer station | Western
Disaggregation of Revenue [Line Items]
Total revenues	61,430	56,630	44,762
Transfer station | Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	1,711	924	0
Transfer station | Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Transportation
Disaggregation of Revenue [Line Items]
Total revenues	20,603	20,626	19,867
Transportation | Eastern
Disaggregation of Revenue [Line Items]
Total revenues	5,298	4,994	5,619
Transportation | Western
Disaggregation of Revenue [Line Items]
Total revenues	15,305	15,632	14,248
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	7,958	6,617	7,519
Landfill gas-to-energy | Eastern
Disaggregation of Revenue [Line Items]
Total revenues	1,661	806	925
Landfill gas-to-energy | Western
Disaggregation of Revenue [Line Items]
Total revenues	6,297	5,811	6,594
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	141,415	115,951	129,179
Processing | Eastern
Disaggregation of Revenue [Line Items]
Total revenues	8,364	7,996	7,370
Processing | Western
Disaggregation of Revenue [Line Items]
Total revenues	2,592	1,958	2,764
Processing | Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Processing | Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	130,459	105,997	119,045
National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	199,408	186,802	180,833
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	$ 199,408	$ 186,802	$ 180,833

BUSINESS COMBINATIONS - Narrati

BUSINESS COMBINATIONS - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) business	Dec. 31, 2023 business subsidiary	Dec. 31, 2022 business
Business Acquisition [Line Items]
Number of businesses acquired	8	7	14
Number of wholly owned subsidiaries acquired | subsidiary		4
Intangible assets, useful life	10 years
Goodwill, expected tax deductible amount | $	$ 120,754
Mid-Atlantic
Business Acquisition [Line Items]
Number of businesses acquired	4
Western
Business Acquisition [Line Items]
Number of businesses acquired	2
Eastern
Business Acquisition [Line Items]
Number of businesses acquired	2
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

BUSINESS COMBINATIONS - Schedul

BUSINESS COMBINATIONS - Schedule of Purchase Price Paid for Acquisitions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Purchase Price:
Cash used in acquisitions, net of cash acquired of $11,687, $1,014, and $—, respectively	$ 468,628	$ 851,839	$ 78,197
Cash Acquired from Acquisition	11,687	1,014	0
Allocated as follows:
Excess purchase price to be allocated to goodwill	1,002,266	735,670	274,458
Transfer Stations Acquisition
Purchase Price:
Cash used in acquisitions, net of cash acquired of $11,687, $1,014, and $—, respectively	469,159	846,711	76,573
Other non-cash consideration	0	0	1,275
Working capital settlements due from sellers	(2,987)	(2,873)	0
Holdbacks and additional consideration due to sellers	1,689	2,729	4,840
Total consideration	467,861	846,567	82,688
Allocated as follows:
Current assets	15,992	19,524	7,644
Land	7,026	8,440	3,141
Buildings and improvements	9,878	28,411	8,576
Machinery, equipment and other	89,995	177,916	11,689
Operating lease right-of-use assets	5,222	11,786	405
Deferred tax liability	(20,392)	(9,058)	0
Current liabilities	(27,755)	(21,417)	(3,812)
Other long-term liabilities	0	(828)	(123)
Operating lease liabilities, less current portion	(5,092)	(9,939)	(282)
Fair value of assets acquired and liabilities assumed	203,103	385,408	41,981
Excess purchase price to be allocated to goodwill	264,758	461,159	40,707
Accounts receivable	12,936	17,002	6,806
Transfer Stations Acquisition | Trade Names
Allocated as follows:
Intangible assets	12,470	4,320	55
Transfer Stations Acquisition | Covenants Not-to-Compete
Allocated as follows:
Intangible assets	10,997	30,860	2,424
Transfer Stations Acquisition | Customer Relationships
Allocated as follows:
Intangible assets	104,762	145,393	12,224
Other non-current assets	$ 0	$ 0	$ 40

BUSINESS COMBINATIONS - Sched_2

BUSINESS COMBINATIONS - Schedule of Unaudited Pro forma Combined Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]
Revenues	$ 1,699,991	$ 1,653,535	$ 1,629,041
Operating income	66,320	79,815	104,422
Net income	$ 8,784	$ 21,111	$ 52,726
Basic weighted average shares outstanding (in shares)	59,576	55,174	51,623
Basic earnings per common share (in dollars per share)	$ 0.15	$ 0.38	$ 1.02
Diluted weighted average shares outstanding diluted (in shares)	59,681	55,274	51,767
Diluted earnings per common share (in dollars per share)	$ 0.15	$ 0.38	$ 1.02

ACCOUNTS RECEIVABLE, NET OF A_3

ACCOUNTS RECEIVABLE, NET OF ALLOWANCE FOR CREDIT LOSSES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 4,066	$ 3,016	$ 3,276
Additions - charged to expense	5,987	2,468	1,893
Additions - reserve for acquired receivables with credit deterioration	870	0	0
Deductions - write offs charged against the allowance, net of recoveries	(2,408)	(1,418)	(2,153)
Balance at end of period	$ 8,515	$ 4,066	$ 3,016

PROPERTY AND EQUIPMENT - Compon

PROPERTY AND EQUIPMENT - Components of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Finance lease right-of-use assets	$ 128,159	$ 101,770
Total property and equipment	2,467,139	2,148,094
Less: accumulated depreciation and amortization	(1,302,324)	(1,167,541)
Property, plant and equipment and finance lease right-of-use assets, net	1,164,815	980,553
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	56,010	47,863
Landfills
Property, Plant and Equipment [Line Items]
Property and equipment, gross	859,602	786,130
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	303,170	262,204
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	318,391	287,175
Rolling stock
Property, Plant and Equipment [Line Items]
Property and equipment, gross	490,571	396,247
Containers
Property, Plant and Equipment [Line Items]
Property and equipment, gross	311,236	266,705
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 104,686	$ 74,408

PROPERTY AND EQUIPMENT - Narrat

PROPERTY AND EQUIPMENT - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 133,928	$ 99,249	$ 78,139
Landfills
Property, Plant and Equipment [Line Items]
Amortization expense	$ 44,498	$ 40,419	$ 31,619

LEASES - Schedule of Lease Cost

LEASES - Schedule of Lease Costs and Other Lease Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Lease cost:
Amortization of right-of-use assets	$ 9,216	$ 7,383
Interest expense	2,594	1,840
Fixed lease cost	17,784	15,318
Short-term lease cost	9,603	5,313
Variable lease cost	780	604
Total lease cost	39,977	30,458
Cash paid for amounts included in the measurement of lease liabilities:
Financing cash flows for finance leases	12,071	8,981
Operating cash flows for operating leases	11,884	10,578
Right-of-use assets obtained in exchange for new finance lease liabilities	28,723	12,211
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 11,686	19,796
Weighted-average remaining lease term - finance leases (years)	5 years 1 month 6 days
Weighted-average remaining lease term - operating leases (years)	9 years 10 months 24 days
Weighted-average discount rate - finance leases	4.60%
Weighted-average discount rate - operating leases	4.80%
Machinery and equipment
Lease cost:
Fixed lease cost	$ 8,021	6,292
Landfills
Lease cost:
Fixed lease cost	$ 9,763	$ 9,026

LEASES - Schedule of Estimated

LEASES - Schedule of Estimated Minimum Future Lease Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Operating Leases
Fiscal year ending December 31, 2025	$ 13,608
Fiscal year ending December 31, 2026	12,719
Fiscal year ending December 31, 2027	11,669
Fiscal year ending December 31, 2028	8,926
Fiscal year ending December 31, 2029	8,656
Thereafter	40,069
Total lease payments	95,647
Less: interest	(20,907)
Lease liability balance	74,740
Finance Leases
Fiscal year ending December 31, 2025	19,951
Fiscal year ending December 31, 2026	15,367
Fiscal year ending December 31, 2027	11,399
Fiscal year ending December 31, 2028	10,750
Fiscal year ending December 31, 2029	8,571
Thereafter	14,366
Total lease payments	80,404
Less: interest	(10,742)
Lease liability balance	$ 69,662	$ 53,066

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS - Summary of Goodwill Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 735,670	$ 274,458
Acquisitions	264,758	461,159
Business Combination Adjustments	1,838	53
Goodwill, ending balance	1,002,266	735,670
Eastern
Goodwill [Roll Forward]
Goodwill, beginning balance	73,893	52,406
Acquisitions	774	21,487
Business Combination Adjustments	0	0
Goodwill, ending balance	74,667	73,893
Western
Goodwill [Roll Forward]
Goodwill, beginning balance	285,056	183,286
Acquisitions	92,825	101,717
Business Combination Adjustments	704	53
Goodwill, ending balance	378,585	285,056
Mid-Atlantic
Goodwill [Roll Forward]
Goodwill, beginning balance	332,247	0
Acquisitions	171,159	332,247
Business Combination Adjustments	946	0
Goodwill, ending balance	504,352	332,247
Resource Solutions
Goodwill [Roll Forward]
Goodwill, beginning balance	44,474	38,766
Acquisitions	0	5,708
Business Combination Adjustments	188	0
Goodwill, ending balance	$ 44,662	$ 44,474

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS - Summary of Intangible Assets by Type (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 474,963	$ 347,469
Less accumulated amortization	(161,495)	(106,040)
Intangible assets, net	313,468	241,429
Covenants Not-to-Compete
Finite-Lived Intangible Assets [Line Items]
Intangible assets	71,568	61,573
Less accumulated amortization	(34,398)	(26,645)
Intangible assets, net	37,170	34,928
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets	377,600	272,571
Less accumulated amortization	(115,305)	(72,227)
Intangible assets, net	262,295	200,344
Trade Names
Finite-Lived Intangible Assets [Line Items]
Intangible assets	25,795	13,325
Less accumulated amortization	(11,792)	(7,168)
Intangible assets, net	$ 14,003	$ 6,157

GOODWILL AND INTANGIBLE ASSET_4

GOODWILL AND INTANGIBLE ASSETS - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible amortization expenses	$ 56,481	$ 31,037	$ 16,593

GOODWILL AND INTANGIBLE ASSET_5

GOODWILL AND INTANGIBLE ASSETS - Summary of Intangible Amortization Expense Estimated (Details) $ in Thousands	Dec. 31, 2024 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Fiscal year ending December 31, 2025	$ 67,846
Fiscal year ending December 31, 2026	60,006
Fiscal year ending December 31, 2027	52,478
Fiscal year ending December 31, 2028	44,749
Fiscal year ending December 31, 2029	34,086
Thereafter	$ 54,303

FINAL CAPPING, CLOSURE AND PO_3

FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 133,904	$ 113,678
Obligations incurred	7,093	5,447
Revisions in estimates	29,537	14,030
Accretion expense	11,350	9,529
Obligations settled	(8,765)	(11,801)
(Recovery) write-off of capping payments	(889)	3,021	$ 0
Ending balance	172,230	$ 133,904	$ 113,678
Southbridge Landfill
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Revisions in estimates	$ 8,385

DEBT - Summary of Debt (Details

DEBT - Summary of Debt (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Weighted-average discount rate - finance leases	4.60%
Finance leases maturing through December 2107; bearing interest at a weighted average of 4.6%	$ 69,662	$ 53,066
Principal amount of debt	1,148,162	1,054,546
Less—unamortized debt issuance costs	14,911	11,103
Debt less unamortized debt issuance costs	1,133,251	1,043,443
Less—current maturities of debt	42,619	35,781
Debt, less current portion	$ 1,090,632	$ 1,007,662
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”) payable quarterly beginning in the fiscal year ended December 31, 2027 with balance due September 2029; bearing interest at 5.967% as of December 31, 2024
Debt Instrument [Line Items]
Stated interest rate	5.967%
Principal amount of debt	$ 800,000	$ 0
Secured Debt | Term loan A facility payable quarterly with balance due December 2026 amended and restated in September 2024 as the Term Loan Facility
Debt Instrument [Line Items]
Principal amount of debt	0	350,000
Secured Debt | Term loan A facility payable quarterly with balance due December 2026 amended and restated in September 2024 as the Term Loan Facility
Debt Instrument [Line Items]
Principal amount of debt	$ 0	419,250
Line of Credit | Revolving credit facility (“Revolving Credit Facility”) due September 2029; bearing interest at term secured overnight financing rate (“Term SOFR”) plus 1.610%
Debt Instrument [Line Items]
Basis spread on variable rate	1.61%
Principal amount of debt	$ 0	0
Line of Credit | Revolving credit facility due December 2026 amended and restated in September 2024 as the Revolving Credit Facility
Debt Instrument [Line Items]
Principal amount of debt	0	0
Unsecured Debt
Debt Instrument [Line Items]
Principal amount of debt	$ 277,000
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	25,000
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	15,000
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	40,000
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	35,000
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	25,000
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	15,000
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	15,000
Unsecured Debt | Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2024 (“FAME Bonds 2024”) due December 2047 - fixed rate interest period bearing interest at 4.625% through May 2035
Debt Instrument [Line Items]
Stated interest rate	4.625%
Principal amount of debt	$ 45,000	0
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	16,000
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%
Principal amount of debt	$ 35,000	35,000
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	11,000
Notes payable maturing through September 2028; bearing interest up to 8.1%
Debt Instrument [Line Items]
Weighted average interest rate	8.10%
Principal amount of debt	$ 1,500	$ 230

DEBT - Credit Facility (Details

DEBT - Credit Facility (Details) - USD ($)	1 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2024	Jun. 30, 2023
Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit drawn		$ 0
Credit Facility
Line of Credit Facility [Line Items]
Additional revolver capacity	$ 200,000,000
Facility term	5 years
Variable rate adjustment	0.04%
Commitment fee percentage, adjustment		0.01%
Floor interest rate		0%
Interest rate, annual increase upon payment default		2%
Interest rate, annual increase upon other event of default		2%
Credit Facility | Minimum
Line of Credit Facility [Line Items]
Commitment fee percentage		0.20%
Credit Facility | Maximum
Line of Credit Facility [Line Items]
Commitment fee percentage		0.40%
Credit Facility | Secured Debt
Line of Credit Facility [Line Items]
Aggregate principal amount issued	$ 800,000,000
Credit Facility | Line of Credit | Minimum | SOFR
Line of Credit Facility [Line Items]
Basis spread on variable rate		1.30%
Credit Facility | Line of Credit | Minimum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate		0.30%
Credit Facility | Line of Credit | Maximum | SOFR
Line of Credit Facility [Line Items]
Basis spread on variable rate		2.175%
Credit Facility | Line of Credit | Maximum | Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate		1.175%
Credit Facility | Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing	700,000,000
Letters of credit sublimit	$ 155,000,000
Remaining capacity		$ 675,403,000
Credit Facility | Line of Credit | Letter of Credit
Line of Credit Facility [Line Items]
Fronting fee		0.25%
Letters of credit		$ 24,597,000
2023 Term Loan A Facility | Secured Debt
Line of Credit Facility [Line Items]
Aggregate principal amount issued			$ 430,000,000

DEBT - Tax-Exempt Financings (D

DEBT - Tax-Exempt Financings (Details) - Unsecured Debt - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Aggregate principal amount outstanding	$ 277,000
Fame Bonds 2024
Debt Instrument [Line Items]
Aggregate principal amount outstanding	45,000	$ 0
Aggregate principal amount issued	45,000
FAME Bonds 2024, Restricted
Debt Instrument [Line Items]
Aggregate principal amount issued	25,000
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	35,000
Aggregate principal amount issued		$ 35,000

DEBT - Components of Interest E

DEBT - Components of Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Interest expense on long-term debt and finance leases	$ 60,077	$ 44,836	$ 21,691
Amortization of debt issuance costs	2,960	2,962	1,903
Letter of credit fees	459	423	458
Less: capitalized interest	(1,085)	(643)	(330)
Total interest expense	$ 62,411	47,578	$ 23,722
GFL Acquisition
Debt Instrument [Line Items]
Amortization of debt issuance costs		395
Twin Bridges Acquisition
Debt Instrument [Line Items]
Amortization of debt issuance costs		$ 101

DEBT - Debt Modification Expens

DEBT - Debt Modification Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt And Derivatives Disclosure [Abstract]
Debt modification expense	$ 1,396	$ 0	$ 0

DEBT - Narrative - Loss from Te

DEBT - Narrative - Loss from Termination of Bridge Financing (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Loss from termination of bridge financing	$ 0	$ 8,191	$ 0
GFL Acquisition
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

DEBT - Summary of Notional Amou

DEBT - Summary of Notional Amounts (Details) - Cash Flow Hedging - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Total
Derivative, Notional Amount [Roll Forward]
Beginning balance	$ 515,000	$ 210,000
Additions	0	390,000
Commencements	0	0
Maturities	0	(85,000)
Ending balance	$ 515,000	515,000
Floor interest rate	0%
Weighted average percentage rate paid	3.60%
Active
Derivative, Notional Amount [Roll Forward]
Beginning balance	$ 515,000	190,000
Additions	0	390,000
Commencements	0	20,000
Maturities	0	(85,000)
Ending balance	515,000	515,000
Forward Starting
Derivative, Notional Amount [Roll Forward]
Beginning balance	0	20,000
Additions	0	0
Commencements	0	(20,000)
Maturities	0	0
Ending balance	$ 0	$ 0

DEBT - Summary of Cash Flow Hed

DEBT - Summary of Cash Flow Hedges (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Accumulated other comprehensive income (loss), net of tax	$ 3,312	$ (1,080)
Designated as hedging instrument | Interest rate swaps
Debt Instrument [Line Items]
Cash flow hedge derivatives, gross asset	7,642	10,364
Cash flow hedge derivatives, gross liability	2,852	11,762
Designated as hedging instrument | Interest rate swaps | Accumulated other comprehensive income (loss), net
Debt Instrument [Line Items]
Accumulated other comprehensive income (loss), before tax	4,790	(1,398)
Accumulated other comprehensive income (loss), tax	(1,478)	318
Accumulated other comprehensive income (loss), net of tax	3,312	(1,080)
Other current assets | Designated as hedging instrument | Interest rate swaps
Debt Instrument [Line Items]
Cash flow hedge derivatives, gross asset	3,606	5,951
Other non-current assets | Designated as hedging instrument | Interest rate swaps
Debt Instrument [Line Items]
Cash flow hedge derivatives, gross asset	4,036	4,413
Other accrued liabilities | Designated as hedging instrument | Interest rate swaps
Debt Instrument [Line Items]
Cash flow hedge derivatives, gross liability	570	0
Other long-term liabilities | Designated as hedging instrument | Interest rate swaps
Debt Instrument [Line Items]
Cash flow hedge derivatives, gross liability	$ 2,282	$ 11,762

DEBT - Fair Value of Debt (Deta

DEBT - Fair Value of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Secured Debt | Term loan A facility (“Term Loan Facility”) payable quarterly beginning in the fiscal year ended December 31, 2027 with balance due September 2029; bearing interest at 5.967% as of December 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Principal amount of debt	$ 800,000	$ 0
Line of Credit | Revolving credit facility (“Revolving Credit Facility”) due September 2029; bearing interest at term secured overnight financing rate (“Term SOFR”) plus 1.610%
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Principal amount of debt	0	$ 0
Fair Value | Industrial Revenue Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt	276,503
Carrying Value | Industrial Revenue Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt	$ 277,000

DEBT - Schedule of Future Matur

DEBT - Schedule of Future Maturities of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Debt And Derivatives Disclosure [Abstract]
Fiscal year ending December 31, 2025	$ 42,619
Fiscal year ending December 31, 2026	13,717
Fiscal year ending December 31, 2027	18,201
Fiscal year ending December 31, 2028	29,968
Fiscal year ending December 31, 2029	790,815
Thereafter	252,842
Principal amount of debt	$ 1,148,162	$ 1,054,546

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Narrative (Details) $ in Thousands	Dec. 31, 2024 USD ($)
Other Commitments [Line Items]
Loss contingency accrual	$ 601
Minimum
Other Commitments [Line Items]
Risk free interest	1.50%
Maximum
Other Commitments [Line Items]
Risk free interest	7.10%

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Schedule of Environmental Liability (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 5,889	$ 6,335
Obligations settled	(452)	(546)
Ending balance	5,532	5,889
Less: current portion	$ 1,597	$ 1,662
Environmental loss contingency, current, statement of financial position, not disclosed	Less: current portion	Less: current portion
Long-term portion	$ 3,935	$ 4,227
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	$ 95	$ 100

COMMITMENTS AND CONTINGENCIES_3

COMMITMENTS AND CONTINGENCIES - Schedule of Future Minimum Rental (Details) $ in Thousands	Dec. 31, 2024 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Fiscal year ending December 31, 2025	$ 1,599
Fiscal year ending December 31, 2026	281
Fiscal year ending December 31, 2027	278
Fiscal year ending December 31, 2028	304
Fiscal year ending December 31, 2029	297
Thereafter	3,406
Total	$ 6,165

COMMITMENTS AND CONTINGENCIES_4

COMMITMENTS AND CONTINGENCIES - Reconciliation of Undiscounted Liability to Amount Recognized in Statements of Financial Position (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Undiscounted liability	$ 6,165
Less discount, net	(633)
Liability balance	$ 5,532	$ 5,889	$ 6,335
Environmental loss contingency, statement of financial position, not disclosed	consolidated balance sheet

COMMITMENTS AND CONTINGENCIES_5

COMMITMENTS AND CONTINGENCIES - Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Cash and cash equivalents	$ 358,303	$ 220,912
Restricted cash	25,000	0
Cash, cash equivalents and restricted cash	$ 383,303	$ 220,912	$ 71,152	$ 33,809

STOCKHOLDERS' EQUITY - Narrativ

STOCKHOLDERS' EQUITY - Narrative (Details) $ / shares in Units, $ in Thousands				12 Months Ended
	Sep. 19, 2024 USD ($) $ / shares shares	Jun. 16, 2023 USD ($) $ / shares shares	Jun. 01, 2023 shares	Dec. 31, 2024 USD ($) vote $ / shares shares	Dec. 31, 2023 USD ($) vote shares	Dec. 31, 2022 USD ($)
Limited Partners' Capital Account [Line Items]
Preferred stock authorized to issue (up to) (in shares) | shares				944,000
Shares issued | shares				0	0
Total fair value of other stock awards vested | $				$ 8,409	$ 12,048	$ 17,011
Income benefit associated with stock-based compensation expense | $				(1,907)	(2,330)	(1,744)
Stock Options
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense | $				579	516	248
Aggregate intrinsic value of stock options exercised | $				2,625	1,302	1,467
Unrecognized stock-based compensation expense, options | $				$ 1,528
Unrecognized stock-based compensation expense, weighted average period				2 years 10 months 24 days
Restricted Stock Awards, Restricted Stock Units and Performance Stock Units
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense | $				$ 11,001	8,116	7,530
Restricted Stock Units
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense | $				$ 5,865
Market-based Performance Stock Units
Limited Partners' Capital Account [Line Items]
Weighted average fair value of market-based performance (in dollars per share) | $ / shares				$ 105.35
Risk-free interest rate				4.30%
Expected volatility				25.30%
Expected dividend yield				0%
Non-Employee Director | Restricted Stock
Limited Partners' Capital Account [Line Items]
Award vesting period				3 years
Maximum | Performance Stock Units
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense | $				$ 5,032
Weighted Average | Restricted Stock Units
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense, weighted average period				2 years
Weighted Average | Performance Stock Units
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense, weighted average period				1 year 8 months 12 days
2016 Incentive Plan
Limited Partners' Capital Account [Line Items]
Expiration period				10 years
2016 Incentive Plan | Minimum
Limited Partners' Capital Account [Line Items]
Award vesting period				1 year
2016 Incentive Plan | Maximum
Limited Partners' Capital Account [Line Items]
Award vesting period				5 years
Amended and Restated 1997 Employee Stock Purchase Plan
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense | $				$ 607	$ 451	$ 376
Class A Common Stock
Limited Partners' Capital Account [Line Items]
Sale of stock, number of shares issued | shares	5,175,000	6,053,000
Public offering price (in dollars per share) | $ / shares	$ 100	$ 85.50
Sale of stock, net proceeds | $	$ 496,245	$ 496,231
Vote for each share held (in votes per share) | vote				1
Common stock, authorized shares (in shares) | shares				4,000,000
Common stock, additional authorized shares (in shares) | shares			400,000
Number of shares available for future grant (in shares) | shares				377,000
Class A Common Stock | Amended 2016 Plan
Limited Partners' Capital Account [Line Items]
Common stock, authorized shares (in shares) | shares				1,750,000
Class A Common Stock | 2016 Incentive Plan
Limited Partners' Capital Account [Line Items]
Common stock, authorized shares (in shares) | shares				2,250,000
Number of shares available for future grant (in shares) | shares				2,205,000
Class A Common Stock | 2006 Incentive Plan
Limited Partners' Capital Account [Line Items]
Common stock, additional authorized shares (in shares) | shares				2,723,000
Class B Common Stock
Limited Partners' Capital Account [Line Items]
Vote for each share held (in votes per share) | vote				10	10

STOCKHOLDERS' EQUITY - Summary

STOCKHOLDERS' EQUITY - Summary of Stock Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) $ / shares shares
Stock Options
Beginning balance, outstanding (in shares) | shares	129
Granted (in shares) | shares	0
Exercised (in shares) | shares	(28)
Forfeited or expired (in shares) | shares	0
Ending balance, outstanding (in shares) | shares	101
Exercisable at end of period (in shares) | shares	42
Weighted Average Exercise Price
Beginning balance, outstanding (in dollars per share) | $ / shares	$ 66.03
Granted (in dollars per share) | $ / shares	0
Exercised (in dollars per share) | $ / shares	12.48
Forfeited or expired (in dollars per share) | $ / shares	0
Ending balance, outstanding (in dollars per share) | $ / shares	80.85
Exercisable at end of period (in dollars per share) | $ / shares	$ 79.50
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Outstanding contractual term	7 years 8 months 12 days
Exercisable contractual term	7 years 6 months
Outstanding aggregate intrinsic value | $	$ 2,518
Exercisable aggregate intrinsic value | $	$ 1,102

STOCKHOLDERS' EQUITY - Summar_2

STOCKHOLDERS' EQUITY - Summary of Restricted Stock, Restricted Stock Unit and Performance Stock Unit Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) $ / shares shares
Performance Stock Units
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Percentage of attainment level	100%
Performance Stock Units | Class A Common Stock
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Number of additional shares (in shares)	130
Additional shares issued	38
Restricted Stock Awards, Restricted Stock Units and Performance Stock Units
Restricted Stock, Restricted Stock Units, and Performance Stock Units
Outstanding, beginning of period (in shares)	181
Granted (in shares)	106
Forfeited or canceled (in shares)	(6)
Outstanding, end of period (in shares)	197
Weighted Average Grant Price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 84.82
Granted (in dollars per share) | $ / shares	99.61
Forfeited or canceled (in dollars per share) | $ / shares	85.70
Outstanding at end of period (in dollars per share) | $ / shares	$ 91.14
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Contractual term (in years)	1 year 10 months 24 days
Aggregate intrinsic value | $	$ 20,882
Restricted Stock Awards, Restricted Stock Units and Performance Stock Units | Unvested
Restricted Stock, Restricted Stock Units, and Performance Stock Units
Outstanding, end of period (in shares)	327
Weighted Average Grant Price
Outstanding at end of period (in dollars per share) | $ / shares	$ 92.55
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Contractual term (in years)	1 year 8 months 12 days
Aggregate intrinsic value | $	$ 34,625
Restricted Stock Awards, Restricted Stock Units and Performance Stock Units | Class A Common Stock
Restricted Stock, Restricted Stock Units, and Performance Stock Units
Class A Common Stock Vested (in shares)	(84)
Weighted Average Grant Price
Class A Common Stock Vested (in dollars per share) | $ / shares	$ 88.60

STOCKHOLDERS' EQUITY - Summar_3

STOCKHOLDERS' EQUITY - Summary of Changes in Balances of Each Component of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 1,021,791	$ 497,900	$ 422,457
Income tax provision (benefit) related to items in other comprehensive income (loss)	(1,797)	4,582	(4,095)
Other comprehensive income (loss), net of tax	4,392	(8,622)	12,645
Ending balance	1,550,839	1,021,791	497,900
Accumulated other comprehensive income (loss), net
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(1,080)	7,542	(5,103)
Other comprehensive income (loss) before reclassifications	14,631	(6,843)	15,297
Amounts reclassified from accumulated other comprehensive income ( loss)	(8,442)	(6,361)	1,443
Income tax provision (benefit) related to items in other comprehensive income (loss)	(1,797)	4,582	(4,095)
Other comprehensive income (loss), net of tax	4,392	(8,622)	12,645
Ending balance	$ 3,312	$ (1,080)	$ 7,542

STOCKHOLDERS' EQUITY - Summar_4

STOCKHOLDERS' EQUITY - Summary of Reclassifications Out of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ 62,411	$ 47,578	$ 23,722
Income before income taxes	21,048	37,045	74,966
Provision for income taxes	7,512	11,646	21,887
Net income	13,536	25,399	53,079
Reclassification out of AOCI | Accumulated other comprehensive income (loss), net
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	8,442	6,361	(1,443)
Provision for income taxes	2,500	2,633	98
Net income	5,942	3,728	(1,541)
Interest rate swaps | Reclassification out of AOCI | Accumulated other comprehensive income (loss), net
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (8,442)	$ (6,361)	$ 1,443

FAIR VALUE OF FINANCIAL INSTR_3

FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Assets:
Derivative Asset, Statement Of Financial Position Extensible Enumeration, Not Disclosed Flag	Interest rate swaps	Interest rate swaps
Restricted assets	$ 2,499	$ 2,203
Liabilities:
Derivative Liability, 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	$ 0
Total assets	2,499	2,203
Liabilities:
Interest rate swaps	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring | Landfills
Assets:
Restricted assets	2,499	2,203
Significant Other Observable Inputs (Level 2) | Recurring
Assets:
Interest rate swaps	7,642	10,364
Total assets	7,642	10,364
Liabilities:
Interest rate swaps	2,852	11,762
Significant Other Observable Inputs (Level 2) | Recurring | Landfills
Assets:
Restricted assets	0	0
Significant Unobservable Inputs (Level 3) | Recurring
Assets:
Interest rate swaps	0	0
Total assets	0	0
Liabilities:
Interest rate swaps	0	0
Significant Unobservable Inputs (Level 3) | Recurring | Landfills
Assets:
Restricted assets	$ 0	$ 0

EMPLOYEE BENEFIT PLANS (Details

EMPLOYEE BENEFIT PLANS (Details) - USD ($) shares in Thousands		12 Months Ended
	Jun. 01, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2019
Employee Stock Purchase Plan [Line Items]
Employer contributions vesting period		2 years
Employer contributions		$ 5,831,000	$ 4,371,000	$ 3,558,000
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		1,402,000
Pension Plan
Employee Stock Purchase Plan [Line Items]
Contributions by employer		$ 500,000	$ 479,000	$ 442,000
Class A Common Stock
Employee Stock Purchase Plan [Line Items]
Discount rate		15%
Common stock, additional authorized shares (in shares)	400
Stock issued under stock purchase plan (in shares)		30	24	22
Stock available for distribution under stock purchase plan (in shares)		377
Salary employees
Employee Stock Purchase Plan [Line Items]
Employer matching contribution, percent of match		50%
Employer matching contribution, percent of employees' annual income		2%
Maximum annual contributions per employee		$ 1,500
First matching contribution | Hourly employees
Employee Stock Purchase Plan [Line Items]
Employer matching contribution, percent of match		100%
Employer matching contribution, percent of employees' annual income		1%
Next matching contribution | Hourly employees
Employee Stock Purchase Plan [Line Items]
Employer matching contribution, percent of match		50%
Employer matching contribution, percent of employees' annual income		3%

INCOME TAXES - Schedule of Bene

INCOME TAXES - Schedule of Benefit for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Federal
Current	$ 911	$ 0	$ 0
Deferred	8,652	8,155	15,645
Total	9,563	8,155	15,645
State
Current	(297)	4,385	5,362
Deferred	(1,754)	(894)	880
Total	(2,051)	3,491	6,242
Provision for income taxes	$ 7,512	$ 11,646	$ 21,887

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Operating Loss Carryforwards [Line Items]
Income tax benefit, valuation allowance release	$ 3,166,000
Valuation allowance	8,456,000	$ 10,986,000
Increase (decrease) in valuation allowance	(2,530,000)
Net deferred tax liability	(19,089,000)
Net operating loss carryforwards not subject to expiration	83,211,000
State net operating loss carryforwards, state and local	125,708,000
General business credit carryforward	3,900,000
Unrecognized tax benefits	0	$ 0
State
Operating Loss Carryforwards [Line Items]
Net deferred tax liability	(19,089,000)
Tax credit carryforwards	$ 0

INCOME TAXES - Schedule of Diff

INCOME TAXES - Schedule of Difference in Benefit for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Federal statutory rate	21%	21%	21%
Tax at statutory rate	$ 4,420	$ 7,779	$ 15,743
State income taxes, net of federal benefit	(1,660)	620	4,203
Change in valuation allowance	68	1,675	459
Federal effect of change in state valuation allowance	0	(312)	282
Expired tax attributes	497	0	0
Non-deductible officer compensation	1,172	996	1,300
Other non-deductible expenses	2,931	809	782
Deductible stock awards	103	(963)	(627)
Tax credits	63	(60)	(83)
Reversal of disproportionate tax effects in other comprehensive (loss) income	0	938	0
Other, net	(82)	164	(172)
Provision for income taxes	$ 7,512	$ 11,646	$ 21,887

INCOME TAXES - Schedule of Defe

INCOME TAXES - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deferred tax assets:
Accrued expenses and reserves	$ 60,319	$ 49,339
Net operating loss carryforwards	26,544	35,571
General business and state tax credit carryforwards	3,900	6,862
Interest expense limitation	10,089	6,690
Stock awards	3,256	2,690
Unrealized loss on swaps	0	375
Other	1,024	1,567
Total deferred tax assets	105,132	103,094
Less: valuation allowance	(8,456)	(10,986)
Total deferred tax assets after valuation allowance	96,676	92,108
Deferred tax liabilities:
Tax over book depreciation of property and equipment	(71,467)	(58,927)
Amortization of intangibles	(42,961)	(22,540)
Unrealized gain on swaps	(1,337)	0
Other	0	(44)
Total deferred tax liabilities	(115,765)	(81,511)
Net deferred tax liability	$ (19,089)
Net deferred tax asset		$ 10,597

OTHER ITEMS AND CHARGES - Narra

OTHER ITEMS AND CHARGES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Unusual or Infrequent Items, or Both [Abstract]
Landfill capping (recovery) charge - veneer failure	$ (1,739)	$ 3,870	$ 0
Expense from acquisition activities	24,879	15,038	4,613
Legal settlement	0	6,150	0
Environmental remediation charge	$ 0	$ 0	$ 759

OTHER ITEMS AND CHARGES - Charg

OTHER ITEMS AND CHARGES - Charges Associated with Closure of Southbridge Landfill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Site Contingency [Line Items]
Southbridge Landfill closure charge	$ 8,385	$ 467	$ 1,436
Southbridge Landfill
Site Contingency [Line Items]
Legal and transaction costs	0	412	684
Landfill closure project charge	8,385	55	752
Southbridge Landfill closure charge	$ 8,385	$ 467	$ 1,436

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ in Thousands			12 Months Ended
	Sep. 19, 2024	Jun. 16, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net income			$ 13,536	$ 25,399	$ 53,079
Denominator:
Unvested restricted stock awards (in shares)			0	0	(1,000)
Effect of weighted average shares outstanding (in shares)			(3,782,000)	(2,821,000)	(68,000)
Basic weighted average common shares outstanding (in shares)			59,576,000	55,174,000	51,623,000
Impact of potentially dilutive securities:
Dilutive effect of stock options and stock awards (in shares)			105,000	100,000	144,000
Diluted weighted average common shares outstanding (in shares)			59,681,000	55,274,000	51,767,000
Antidilutive potentially issuable shares (in shares)			25,000	93,000	111,000
Class A Common Stock
Denominator:
Common stock, shares outstanding (in shares)			62,370,000	57,007,000	50,704,000
Impact of potentially dilutive securities:
Sale of stock, number of shares issued	5,175,000	6,053,000
Class B Common Stock
Denominator:
Common stock, shares outstanding (in shares)			988,000	988,000	988,000

RELATED PARTY TRANSACTIONS (Det

RELATED PARTY TRANSACTIONS (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Apr. 30, 1994 lease
Related Party Transaction [Line Items]
Total services purchased	$ 7,762	$ 7,682	$ 12,297
Current liabilities	307,317	278,858
Revenues	1,557,283	1,264,542	1,085,089
Number of leases | lease				2
Amortization of right-of-use assets	9,216	7,383
Accrued costs associated with post-closure obligations	172,230	133,904	113,678
Landfills
Related Party Transaction [Line Items]
Landfill post-closure cost	14	3	10
Accrued costs associated with post-closure obligations	17	17
Related Party
Related Party Transaction [Line Items]
Current liabilities	477	595
Revenues	242	241	141
Leases monthly payments	34
Amortization of right-of-use assets	$ 554	$ 284	$ 273

SEGMENT REPORTING - Narrative (

SEGMENT REPORTING - Narrative (Details)	12 Months Ended
	Dec. 31, 2024 segment
Solid Waste Operations
Segment Reporting Information [Line Items]
Number of operating segments	3

SEGMENT REPORTING - Summary of

SEGMENT REPORTING - Summary of Financial Information by Reportable Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenues	$ 1,557,283	$ 1,264,542	$ 1,085,089
Cost of operations	1,027,336	832,038	723,117
General and administration	190,754	155,847	133,419
Depreciation and amortization	234,907	170,705	126,351
Expense from acquisition activities	24,879	15,038	4,613
Legal settlement	0	6,150	0
Landfill capping (recovery) charge - veneer failure	(1,739)	3,870	0
Southbridge Landfill closure charge	8,385	467	1,436
Environmental remediation charge	0	0	759
Operating income	72,761	80,427	95,394
Interest expense (income), net	51,983	36,837	23,013
Other income, net	(270)	6,545	(2,585)
Income before income taxes	21,048	37,045	74,966
Capital expenditures	203,227	154,907	130,960
Total assets	3,230,068	2,535,470	1,449,215
Solid Waste Operations
Segment Reporting Information [Line Items]
Revenues	1,227,416	971,743	785,211
Solid Waste Operations | Eastern
Segment Reporting Information [Line Items]
Revenues	416,678	374,463	340,058
Solid Waste Operations | Western
Segment Reporting Information [Line Items]
Revenues	591,214	511,640	445,153
Solid Waste Operations | Mid-Atlantic
Segment Reporting Information [Line Items]
Revenues	219,524	85,640	0
Resource Solutions
Segment Reporting Information [Line Items]
Revenues	329,867	292,799	299,878
Inter-company revenue
Segment Reporting Information [Line Items]
Revenues	(328,949)	(281,736)	(239,951)
Cost of operations	(328,949)	(281,736)	(239,951)
Inter-company revenue | Solid Waste Operations
Segment Reporting Information [Line Items]
Revenues	315,881	266,399	234,217
Inter-company revenue | Solid Waste Operations | Eastern
Segment Reporting Information [Line Items]
Revenues	104,529	92,938	83,201
Inter-company revenue | Solid Waste Operations | Western
Segment Reporting Information [Line Items]
Revenues	208,963	173,044	151,016
Inter-company revenue | Solid Waste Operations | Mid-Atlantic
Segment Reporting Information [Line Items]
Revenues	2,389	417	0
Inter-company revenue | Resource Solutions
Segment Reporting Information [Line Items]
Revenues	13,068	15,337	5,734
Operating Segments | Solid Waste Operations
Segment Reporting Information [Line Items]
Revenues	1,543,297	1,238,142	1,019,428
Cost of operations	1,078,939	854,471	712,262
General and administration	71,425	60,894	49,956
Depreciation and amortization	212,959	153,435	111,789
Expense from acquisition activities	18,548	9,065	3,233
Legal settlement		6,150
Landfill capping (recovery) charge - veneer failure	(1,739)	3,870
Southbridge Landfill closure charge	8,385	467	1,436
Environmental remediation charge			759
Operating income	154,780	149,790	139,993
Interest expense (income), net	1,126	1,018	1,073
Capital expenditures	167,590	131,794	103,691
Total assets	2,519,249	1,988,752	1,110,553
Operating Segments | Solid Waste Operations | Eastern
Segment Reporting Information [Line Items]
Revenues	521,207	467,401	423,259
Cost of operations	372,123	335,896	312,446
General and administration	24,101	24,416	21,851
Depreciation and amortization	56,760	50,881	47,673
Expense from acquisition activities	384	352	898
Legal settlement		2,614
Landfill capping (recovery) charge - veneer failure	0	0
Southbridge Landfill closure charge	8,385	467	1,436
Environmental remediation charge			0
Operating income	59,454	52,775	38,955
Interest expense (income), net	763	638	565
Capital expenditures	44,388	43,817	38,501
Total assets	444,295	434,323	372,895
Operating Segments | Solid Waste Operations | Western
Segment Reporting Information [Line Items]
Revenues	800,177	684,684	596,169
Cost of operations	545,823	458,281	399,816
General and administration	33,852	31,672	28,105
Depreciation and amortization	105,563	82,291	64,116
Expense from acquisition activities	3,349	3,421	2,335
Legal settlement		3,536
Landfill capping (recovery) charge - veneer failure	(1,739)	3,870
Southbridge Landfill closure charge	0	0	0
Environmental remediation charge			759
Operating income	113,329	101,613	101,038
Interest expense (income), net	369	380	508
Capital expenditures	100,329	82,706	65,190
Total assets	1,233,688	1,001,090	737,658
Operating Segments | Solid Waste Operations | Mid-Atlantic
Segment Reporting Information [Line Items]
Revenues	221,913	86,057	0
Cost of operations	160,993	60,294	0
General and administration	13,472	4,806	0
Depreciation and amortization	50,636	20,263	0
Expense from acquisition activities	14,815	5,292	0
Legal settlement		0
Landfill capping (recovery) charge - veneer failure	0	0
Southbridge Landfill closure charge	0	0	0
Environmental remediation charge			0
Operating income	(18,003)	(4,598)	0
Interest expense (income), net	(6)	0	0
Capital expenditures	22,873	5,271	0
Total assets	841,266	553,339	0
Operating Segments | Resource Solutions
Segment Reporting Information [Line Items]
Revenues	342,935	308,136	305,612
Cost of operations	276,582	259,273	250,775
General and administration	19,574	18,149	16,460
Depreciation and amortization	18,254	14,202	12,082
Expense from acquisition activities	105	102	564
Legal settlement		0
Landfill capping (recovery) charge - veneer failure	0	0
Southbridge Landfill closure charge	0	0	0
Environmental remediation charge			0
Operating income	28,420	16,410	25,731
Interest expense (income), net	117	143	146
Capital expenditures	25,932	14,586	15,172
Total assets	256,188	253,090	191,118
Corporate Entities
Segment Reporting Information [Line Items]
Cost of operations	764	30	31
General and administration	99,755	76,804	67,003
Depreciation and amortization	3,694	3,068	2,480
Expense from acquisition activities	6,226	5,871	816
Legal settlement		0
Landfill capping (recovery) charge - veneer failure	0	0
Southbridge Landfill closure charge	0	0	0
Environmental remediation charge			0
Operating income	(110,439)	(85,773)	(70,330)
Interest expense (income), net	50,740	35,676	21,794
Capital expenditures	9,705	8,527	12,097
Total assets	$ 454,631	$ 293,628	$ 147,544

SEGMENT REPORTING - Summary o_2

SEGMENT REPORTING - Summary of Revenue Attributable to Services Provided by Company (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenue from External Customer [Line Items]
Revenues	$ 1,557,283	$ 1,264,542	$ 1,085,089
Solid Waste Operations
Revenue from External Customer [Line Items]
Revenues	1,227,416	971,743	785,211
Resource Solutions
Revenue from External Customer [Line Items]
Revenues	$ 329,867	$ 292,799	$ 299,878
Product concentration risk | Revenue
Revenue from External Customer [Line Items]
Revenues percentage	100%	100%	100%
Product concentration risk | Revenue | Solid Waste Operations
Revenue from External Customer [Line Items]
Revenues percentage	78.80%	76.80%	72.40%
Product concentration risk | Revenue | Resource Solutions
Revenue from External Customer [Line Items]
Revenues percentage	21.20%	23.20%	27.60%
Collection | Solid Waste Operations
Revenue from External Customer [Line Items]
Revenues	$ 961,784	$ 710,590	$ 539,587
Collection | Product concentration risk | Revenue | Solid Waste Operations
Revenue from External Customer [Line Items]
Revenues percentage	61.80%	56.20%	49.70%
Disposal | Solid Waste Operations
Revenue from External Customer [Line Items]
Revenues	$ 246,718	$ 244,582	$ 227,971
Disposal | Product concentration risk | Revenue | Solid Waste Operations
Revenue from External Customer [Line Items]
Revenues percentage	15.80%	19.30%	21%
Landfill gas-to-energy | Solid Waste Operations
Revenue from External Customer [Line Items]
Revenues	$ 7,958	$ 6,617	$ 7,519
Landfill gas-to-energy | Product concentration risk | Revenue | Solid Waste Operations
Revenue from External Customer [Line Items]
Revenues percentage	0.50%	0.50%	0.70%
Processing | Solid Waste Operations
Revenue from External Customer [Line Items]
Revenues	$ 10,956	$ 9,954	$ 10,134
Processing | Resource Solutions
Revenue from External Customer [Line Items]
Revenues	$ 130,459	$ 105,997	$ 119,045
Processing | Product concentration risk | Revenue | Solid Waste Operations
Revenue from External Customer [Line Items]
Revenues percentage	0.70%	0.80%	1%
Processing | Product concentration risk | Revenue | Resource Solutions
Revenue from External Customer [Line Items]
Revenues percentage	8.40%	8.40%	10.90%
National Accounts | Resource Solutions
Revenue from External Customer [Line Items]
Revenues	$ 199,408	$ 186,802	$ 180,833
National Accounts | Product concentration risk | Revenue | Resource Solutions
Revenue from External Customer [Line Items]
Revenues percentage	12.80%	14.80%	16.70%