Casella Waste Systems (CWST) 10-Q 31 Oct 24 2024 Q3 Quarterly report Financial data

COVER

COVER - shares	9 Months Ended
	Sep. 30, 2024	Oct. 15, 2024
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Central Index Key	0000911177
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Amendment Flag	false
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		62,325,452
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		988,200

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
CURRENT ASSETS:
Cash and cash equivalents	$ 518,977	$ 220,912
Accounts receivable, net of allowance for credit losses of $7,649 and $4,066, respectively	168,088	157,324
Refundable income taxes	5,010	3,089
Prepaid expenses	22,657	17,223
Inventory	20,240	17,859
Other current assets	8,079	9,918
Total current assets	743,051	426,325
Property and equipment, net of accumulated depreciation and amortization of $1,261,899 and $1,167,541, respectively	1,059,716	980,553
Operating lease right-of-use assets	102,445	100,844
Goodwill	907,876	735,670
Intangible assets, net	273,312	241,429
Restricted assets	2,422	2,203
Cost method investments	10,967	10,967
Deferred income taxes	0	11,224
Other non-current assets	23,440	26,255
Total assets	3,123,229	2,535,470
CURRENT LIABILITIES:
Current maturities of debt	38,368	35,781
Current operating lease liabilities	10,492	9,039
Accounts payable	101,632	116,794
Accrued payroll and related expenses	25,045	22,657
Accrued interest	2,928	3,886
Contract liabilities	47,798	31,472
Current accrued final capping, closure and post-closure costs	15,991	10,773
Other accrued liabilities	49,000	48,456
Total current liabilities	291,254	278,858
Debt, less current portion	1,045,509	1,007,662
Operating lease liabilities, less current portion	68,601	66,074
Accrued final capping, closure and post-closure costs, less current portion	133,644	123,131
Deferred income taxes	15,385	627
Other long-term liabilities	37,306	37,327
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY:
Additional paid-in capital	1,673,442	1,168,812
Accumulated deficit	(137,861)	(146,521)
Accumulated other comprehensive loss, net of tax	(4,684)	(1,080)
Total stockholders' equity	1,531,530	1,021,791
Total liabilities and stockholders' equity	3,123,229	2,535,470
Class A Common Stock
STOCKHOLDERS' EQUITY:
Common stock	623	570
Class B Common Stock
STOCKHOLDERS' EQUITY:
Common stock	$ 10	$ 10

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024 USD ($) vote $ / shares shares	Dec. 31, 2023 USD ($) vote $ / shares shares
Accounts receivable - trade, allowance for credit losses | $	$ 7,649	$ 4,066
Accumulated depreciation and amortization | $	$ 1,261,899	$ 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)	62,325,000	57,007,000
Common stock, shares outstanding (in shares)	62,325,000	57,007,000
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

UNAUDITED CONSOLIDATED STATEMEN

UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Statement [Abstract]
Revenues	$ 411,627	$ 352,735	$ 1,129,797	$ 904,975
Operating expenses:
Cost of operations	267,117	226,303	741,695	592,865
General and administration	47,030	41,177	138,547	112,721
Depreciation and amortization	59,174	47,736	168,549	116,095
Southbridge Landfill closure charge	8,477	70	8,477	276
Expense from acquisition activities	5,450	3,261	18,297	9,801
Legal settlement	0	0	0	6,150
Total operating expenses	387,248	318,547	1,075,565	837,908
Operating income	24,379	34,188	54,232	67,067
Other expense (income):
Interest income	(1,380)	(5,525)	(6,817)	(7,820)
Interest expense	15,748	15,748	46,951	31,708
Loss from termination of bridge financing	0	0	0	8,191
Other income	(412)	(225)	(1,239)	(1,019)
Other expense, net	13,956	9,998	38,895	31,060
Income before income taxes	10,423	24,190	15,337	36,007
Provision for income taxes	4,652	6,018	6,677	8,797
Net income	$ 5,771	$ 18,172	$ 8,660	$ 27,210
Basic earnings per share attributable to common stockholders:
Weighted average common shares outstanding, basic (in shares)	58,808	57,962	58,318	54,228
Basic earnings per common share (in dollars per share)	$ 0.10	$ 0.31	$ 0.15	$ 0.50
Diluted earnings per share attributable to common stockholders:
Weighted average common shares outstanding, diluted (in shares)	58,921	58,062	58,415	54,325
Diluted earnings per common share (in dollars per share)	$ 0.10	$ 0.31	$ 0.15	$ 0.50

UNAUDITED CONSOLIDATED STATEM_2

UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 5,771	$ 18,172	$ 8,660	$ 27,210
Hedging activity:
Interest rate swap settlements	2,339	1,763	6,957	4,108
Interest rate swap expense reclassified into interest expense	(2,289)	(1,805)	(6,900)	(4,181)
Unrealized (loss) gain resulting from changes in fair value of derivative instruments	(14,723)	2,621	(5,216)	2,738
Other comprehensive (loss) income, before tax	(14,673)	2,579	(5,159)	2,665
Income tax (benefit) provision related to items of other comprehensive (loss) income	(4,168)	707	(1,555)	727
Other comprehensive (loss) income, net of tax	(10,505)	1,872	(3,604)	1,938
Comprehensive (loss) income	$ (4,734)	$ 20,044	$ 5,056	$ 29,148

UNAUDITED CONSOLIDATED STATEM_3

UNAUDITED CONSOLIDATED STATEMENTS 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, 2022	$ 497,900	$ 661,761	$ (171,920)	$ 7,542		$ 507		$ 10
Beginning balance (in shares) at Dec. 31, 2022						50,704,000		988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	0	(2)				$ 2
Issuance of Class A common stock (in shares)						194,000
Stock-based compensation	1,976	1,976
Net (loss) income	3,548		3,548
Other comprehensive income (loss), hedging activity	(1,769)			(1,769)
Ending balance at Mar. 31, 2023	501,655	663,735	(168,372)	5,773		$ 509		$ 10
Ending balance (in shares) at Mar. 31, 2023						50,898,000		988,000
Beginning balance at Dec. 31, 2022	497,900	661,761	(171,920)	7,542		$ 507		$ 10
Beginning balance (in shares) at Dec. 31, 2022						50,704,000		988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	27,210
Other comprehensive income (loss), hedging activity	1,938
Ending balance at Sep. 30, 2023	1,030,867	1,165,517	(144,710)	9,480		$ 570		$ 10
Ending balance (in shares) at Sep. 30, 2023					56,994,000	56,994,000	988,000	988,000
Beginning balance at Mar. 31, 2023	501,655	663,735	(168,372)	5,773		$ 509		$ 10
Beginning balance (in shares) at Mar. 31, 2023						50,898,000		988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A common stock - equity offering, net of stock issuance costs	496,238	496,177				$ 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	799	799
Issuance of Class A common stock (in shares)						23,000
Stock-based compensation	2,366	2,366
Net (loss) income	5,490		5,490
Other comprehensive income (loss), hedging activity	1,835			1,835
Ending balance at Jun. 30, 2023	1,008,383	1,163,077	(162,882)	7,608		$ 570		$ 10
Ending balance (in shares) at Jun. 30, 2023						56,974,000		988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A common stock - stock issuance costs	(7)	(7)
Issuances of Class A common stock	89	89
Issuance of Class A common stock (in shares)						20,000
Stock-based compensation	2,358	2,358
Net (loss) income	18,172		18,172
Other comprehensive income (loss), hedging activity	1,872			1,872
Ending balance at Sep. 30, 2023	1,030,867	1,165,517	(144,710)	9,480		$ 570		$ 10
Ending balance (in shares) at Sep. 30, 2023					56,994,000	56,994,000	988,000	988,000
Beginning balance at Dec. 31, 2023	1,021,791	1,168,812	(146,521)	(1,080)		$ 570		$ 10
Beginning balance (in shares) at Dec. 31, 2023					57,007,000	57,007,000	988,000	988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	0	(1)				$ 1
Issuance of Class A common stock (in shares)						113,000
Stock-based compensation	2,135	2,135
Net (loss) income	(4,117)		(4,117)
Other comprehensive income (loss), hedging activity	6,115			6,115
Ending balance at Mar. 31, 2024	1,025,924	1,170,946	(150,638)	5,035		$ 571		$ 10
Ending balance (in shares) at Mar. 31, 2024						57,120,000		988,000
Beginning balance at Dec. 31, 2023	1,021,791	1,168,812	(146,521)	(1,080)		$ 570		$ 10
Beginning balance (in shares) at Dec. 31, 2023					57,007,000	57,007,000	988,000	988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	8,660
Other comprehensive income (loss), hedging activity	(3,604)
Ending balance at Sep. 30, 2024	1,531,530	1,673,442	(137,861)	(4,684)		$ 623		$ 10
Ending balance (in shares) at Sep. 30, 2024					62,325,000	62,325,000	988,000	988,000
Beginning balance at Mar. 31, 2024	1,025,924	1,170,946	(150,638)	5,035		$ 571		$ 10
Beginning balance (in shares) at Mar. 31, 2024						57,120,000		988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	1,124	1,124
Issuance of Class A common stock (in shares)						25,000
Stock-based compensation	2,674	2,674
Net (loss) income	7,006		7,006
Other comprehensive income (loss), hedging activity	786			786
Ending balance at Jun. 30, 2024	1,037,514	1,174,744	(143,632)	5,821		$ 571		$ 10
Ending balance (in shares) at Jun. 30, 2024						57,145,000		988,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A common stock - equity offering, net of stock issuance costs	496,126	496,074				$ 52
Issuance of Class A common stock - equity offering, net of stock issuance costs (in shares)						5,175,000
Issuance of Class A common stock (in shares)						5,000
Stock-based compensation	2,624	2,624
Net (loss) income	5,771		5,771
Other comprehensive income (loss), hedging activity	(10,505)			(10,505)
Ending balance at Sep. 30, 2024	$ 1,531,530	$ 1,673,442	$ (137,861)	$ (4,684)		$ 623		$ 10
Ending balance (in shares) at Sep. 30, 2024					62,325,000	62,325,000	988,000	988,000

UNAUDITED CONSOLIDATED STATEM_4

UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash Flows from Operating Activities:
Net income	$ 8,660	$ 27,210
Adjustment to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	168,549	116,095
Interest accretion on landfill and environmental remediation liabilities	8,758	7,470
Amortization of debt issuance costs	2,224	2,221
Stock-based compensation	7,433	6,699
Operating lease right-of-use assets expense	13,119	10,956
Disposition of assets, other items and charges, net	12,459	279
Loss from termination of bridge financing	0	8,191
Deferred income taxes	3,424	5,233
Changes in assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable	(8,865)	(23,298)
Landfill operating lease contract expenditures	(3,486)	(3,336)
Accounts payable	(20,532)	24,568
Prepaid expenses, inventories and other assets	(6,086)	(10,112)
Accrued expenses, contract liabilities and other liabilities	(14,063)	(14,351)
Net cash provided by operating activities	171,594	157,825
Cash Flows from Investing Activities:
Acquisitions, net of cash acquired	(259,196)	(847,763)
Additions to intangible assets	(265)	0
Additions to property and equipment	(126,361)	(90,364)
Proceeds from sale of property and equipment	1,047	971
Proceeds from property insurance settlement	146	0
Net cash used in investing activities	(384,629)	(937,156)
Cash Flows from Financing Activities:
Proceeds from debt borrowings	801,750	465,000
Principal payments on debt	(780,771)	(18,563)
Payments of debt issuance costs	(6,448)	(12,759)
Proceeds from the exercise of share based awards	0	89
Proceeds from the public offering of Class A common stock	496,569	496,231
Net cash provided by financing activities	511,100	929,998
Net increase in cash, cash equivalents and restricted cash	298,065	150,667
Cash, cash equivalents and restricted cash, beginning of period	220,912	71,152
Cash, cash equivalents and restricted cash, end of period	518,977	221,819
Cash paid during the period for:
Cash interest payments	45,685	28,626
Cash income tax payments	5,135	9,689
Supplemental Disclosure of Non-Cash Activities:
Non-current assets obtained through long-term financing obligations	23,679	8,053
Right-of-use assets obtained in exchange for operating lease obligations	$ 10,776	$ 18,558

BASIS OF PRESENTATION

BASIS OF PRESENTATION	9 Months Ended
	Sep. 30, 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 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 unaudited 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. Our significant accounting policies are more fully discussed in Item 8. “ Financial Statements and Supplementary Data ” of our Annual Report on Form 10-K for the fiscal year ended December 31, 2023 (“fiscal year 2023”), which was filed with the SEC on February 16, 2024 (“2023 Form 10-K”). 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 the opinion of management, these consolidated financial statements include all adjustments, including normal recurring and nonrecurring adjustments, as applicable, necessary for a fair statement of the financial position, results of operations and cash flows for the periods presented. The results for the three and nine months ended September 30, 2024 may not be indicative of the results for any other interim period or the entire fiscal year. The consolidated financial statements presented herein should be read in conjunction with our audited consolidated financial statements included in our 2023 Form 10-K. Subsequent Events We have evaluated subsequent events or transactions that have occurred after the consolidated balance sheet date of September 30, 2024 through the date of filing of the consolidated financial statements with the SEC on this Quarterly Report on Form 10-Q. Except as disclosed, no material subsequent events have occurred since September 30, 2024 through the date of this filing that would require recognition or adjustments to our disclosures in our consolidated financial statements.

ACCOUNTING CHANGES

ACCOUNTING CHANGES	9 Months Ended
	Sep. 30, 2024
Accounting Changes and Error Corrections [Abstract]
ACCOUNTING CHANGES	ACCOUNTING CHANGES The following table provides a brief description of Accounting Standards Updates (“ASU”) to the Accounting Standards Codification (“ASC”) issued by the Financial Accounting Standards Board (“FASB”) 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 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 do not expect the adoption of this guidance to have a material impact on our consolidated financial statements, however, the adoption of this guidance will have an impact on reportable operating segment disclosures within the accompanying notes to our consolidated financial statements. This guidance does not change how we identify our operating segments, aggregate them or apply quantitative thresholds to determine our reportable segments. This guidance is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. ASU No. 2023-09: Improvements to Income Tax Disclosures (Topic 740) Requires entities to provide additional disclosure related to the transparency and decision usefulness of income tax disclosures, including additional disclosure around the rate reconciliation and income taxes paid. We do not expect the adoption of this guidance to have a material impact on our consolidated financial statements, however, the adoption of this guidance will have an impact on income tax disclosures within the accompanying notes to our consolidated financial statements. This guidance is effective for fiscal years beginning after December 15, 2024, with early adoption permitted.

REVENUE RECOGNITION

REVENUE RECOGNITION	9 Months Ended
	Sep. 30, 2024
Revenue from Contract with Customer [Abstract]
REVENUE RECOGNITION	REVENUE RECOGNITION Revenues associated with our solid waste operations are derived mainly from solid waste collection and disposal services, including landfill, transfer station and transportation services, landfill gas-to-energy services and processing services. Revenues associated with our resource renewal operations are derived from processing services and non-processing services, which we refer to as our National Accounts business. The following tables set forth revenues disaggregated by service line and timing of revenue recognition by operating segment for each of the three and nine months ended September 30, 2024 and 2023: Three Months Ended September 30, 2024 Eastern Western Mid-Atlantic Resource Solutions Total Revenues Collection $ 79,291 $ 109,740 $ 63,548 $ — $ 252,579 Landfill 7,745 18,019 — — 25,764 Transfer station 18,862 16,890 457 — 36,209 Transportation 1,363 4,117 — — 5,480 Landfill gas-to-energy 301 1,350 — — 1,651 Processing 2,842 640 — 34,954 38,436 National Accounts — — — 51,508 51,508 Total revenues $ 110,404 $ 150,756 $ 64,005 $ 86,462 $ 411,627 Transferred at a point-in-time $ 122 $ 645 $ — $ 16,588 $ 17,355 Transferred over time 110,282 150,111 64,005 69,874 394,272 Total revenues $ 110,404 $ 150,756 $ 64,005 $ 86,462 $ 411,627 Three Months Ended September 30, 2023 Eastern Western Mid-Atlantic (1) Resource Solutions Total Revenues Collection $ 68,944 $ 93,924 $ 43,225 $ — $ 206,093 Landfill 7,588 18,563 — — 26,151 Transfer station 16,963 17,491 497 — 34,951 Transportation 1,328 3,907 — — 5,235 Landfill gas-to-energy 208 1,589 — — 1,797 Processing 2,476 545 — 27,782 30,803 National Accounts — — — 47,705 47,705 Total revenues $ 97,507 $ 136,019 $ 43,722 $ 75,487 $ 352,735 Transferred at a point-in-time $ 121 $ 651 $ — $ 8,549 $ 9,321 Transferred over time 97,386 135,368 43,722 66,938 343,414 Total revenues $ 97,507 $ 136,019 $ 43,722 $ 75,487 $ 352,735 Nine Months Ended September 30, 2024 Eastern Western Mid-Atlantic Resource Solutions Total Revenues Collection $ 225,622 $ 315,546 $ 146,728 $ — $ 687,896 Landfill 21,940 48,156 — — 70,096 Transfer station 51,626 45,111 1,292 — 98,029 Transportation 4,071 10,520 — — 14,591 Landfill gas-to-energy 1,298 4,846 — — 6,144 Processing 6,342 1,948 — 97,992 106,282 National Accounts — — — 146,759 146,759 Total revenues $ 310,899 $ 426,127 $ 148,020 $ 244,751 $ 1,129,797 Transferred at a point-in-time $ 361 $ 1,940 $ — $ 44,304 $ 46,605 Transferred over time 310,538 424,187 148,020 200,447 1,083,192 Total revenues $ 310,899 $ 426,127 $ 148,020 $ 244,751 $ 1,129,797 Nine Months Ended September 30, 2023 Eastern Western Mid-Atlantic (1) Resource Solutions Total Revenues Collection $ 194,801 $ 257,891 $ 43,225 $ — $ 495,917 Landfill 21,109 53,943 — — 75,052 Transfer station 48,643 42,181 497 — 91,321 Transportation 3,718 11,342 — — 15,060 Landfill gas-to-energy 594 4,448 — — 5,042 Processing 5,875 1,476 — 75,970 83,321 National Accounts — — — 139,262 139,262 Total revenues $ 274,740 $ 371,281 $ 43,722 $ 215,232 $ 904,975 Transferred at a point-in-time $ 339 $ 2,072 $ — $ 23,121 $ 25,532 Transferred over time 274,401 369,209 43,722 192,111 879,443 Total revenues $ 274,740 $ 371,281 $ 43,722 $ 215,232 $ 904,975 (1) Operations under the Mid-Atlantic region commenced July 1, 2023. Payments to customers that are not in exchange for a distinct good or service are recorded as a reduction of revenues. Rebates to certain customers associated with payments for recycled or organic materials that are received and subsequently processed and sold to other third-parties amounted to $9,084 and $24,615 in the three and nine months ended September 30, 2024, respectively, and $4,617 and $17,575 in the three and nine months ended September 30, 2023, respectively. 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 the three and nine months ended September 30, 2024 or September 30, 2023 from performance obligations satisfied in previous periods. Contract receivables, which are included in accounts receivable, net in our consolidated balance sheets are recorded when billed or when related revenue is earned, if earlier, and represent claims against third-parties that will be settled in cash. Accounts receivable, net includes receivables from contracts of $174,216 and $158,931 as of September 30, 2024 and December 31, 2023, respectively. Certain customers are billed in advance and, accordingly, recognition of the related revenues for which payment has been received is deferred as a contract liability until the services are provided and control transferred to the customer. We recognized contract liabilities of $47,798 and $31,472 as of September 30, 2024 and December 31, 2023, respectively. Due to the short term nature of advanced billings, substantially all of the deferred revenue recognized as a contract liability as of December 31, 2023 and December 31, 2022 was recognized as revenue during the nine months ended September 30, 2024 and September 30, 2023, respectively, when the services were performed.

BUSINESS COMBINATIONS

BUSINESS COMBINATIONS	9 Months Ended
	Sep. 30, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]
BUSINESS COMBINATIONS	BUSINESS COMBINATIONS Subsequent to September 30, 2024, we completed the purchase of all equity interests of Royal Carting and Welsh Sanitation and related real estate assets. This acquisition includes collection and transfer operations in the middle and lower Hudson Valley regions of New York as well as western Connecticut. In the nine months ended September 30, 2024, we acquired five businesses: three 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; and two of which are tuck-in operations in our Eastern region. In the nine months ended September 30, 2023, we acquired five businesses: the equity interests of four wholly owned subsidiaries of GFL Environmental Inc., which included solid waste collection, transfer and recycling operations in Pennsylvania, Maryland and Delaware (“GFL Acquisition”); the assets of Consolidated Waste Services, LLC and its affiliates (dba Twin Bridges), a collection, transfer and recycling business in the greater Albany, New York area (“Twin Bridges Acquisition”); as well as three solid-waste collection businesses that provide collection, transfer and recycling services. The operating results of the businesses acquired prior to September 30, 2024 have been included in the accompanying unaudited 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. 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. Such assets are amortized over a two-year to ten-year period from the date of acquisition. Goodwill acquired is primarily associated with the value of projected discounted cash flows, based on the current and anticipated operating performance of the business, in excess of the specific values allocated to other assets, new growth opportunities arising from the acquisitions, and expected synergies from combining the acquired businesses with our existing operations and implementing our operating strategies. Substantially all amounts recorded to goodwill are expected to be deductible for tax purposes. A summary of the purchase price and the purchase price allocation for acquisitions follows: Nine Months Ended 2024 2023 Purchase Price: Cash used in acquisitions, net of cash acquired $ 261,235 $ 842,635 Working capital settlements (2,633) — Holdbacks and additional consideration owed 1,575 2,435 Total consideration $ 260,177 $ 845,070 Allocated as follows: Current assets $ 7,309 $ 19,297 Property, plant and equipment: Land 1,310 6,760 Buildings and improvements 1,004 29,636 Machinery and equipment 56,396 175,309 Operating lease right-of-use assets 5,222 11,732 Intangible assets: Trade names 1,970 — Covenants not-to-compete 10,754 37,648 Customer relationships 57,713 145,553 Deferred tax liability (23,509) (11,013) Current liabilities (23,268) (21,724) Operating lease liabilities, less current portion (5,092) (9,939) Other long-term liabilities — (828) Fair value of assets acquired and liabilities assumed 89,809 382,431 Excess purchase price allocated to goodwill $ 170,368 $ 462,639 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 the nine months ended September 30, 2024 are subject to change. Amounts in the nine months ended September 30, 2023 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 operational results prepared as though each acquisition completed since the beginning of the prior fiscal year had occurred as of January 1, 2023 is as follows: Three Months Ended Nine Months Ended 2024 2023 2024 2023 Revenues $ 419,593 $ 400,081 $ 1,195,575 $ 1,164,131 Operating income $ 23,891 $ 33,298 $ 51,151 $ 72,018 Net income $ 5,481 $ 16,765 $ 5,961 $ 26,723 Basic earnings per share attributable to common stockholders: Weighted average common shares outstanding 58,808 57,962 58,318 54,228 Basic earnings per common share $ 0.09 $ 0.29 $ 0.10 $ 0.49 Diluted earnings per share attributable to common stockholders: Weighted average common shares outstanding 58,921 58,062 58,415 54,325 Diluted earnings per common share $ 0.09 $ 0.29 $ 0.10 $ 0.49 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 occurred as of January 1, 2023 or of 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 the result of the integration and consolidation of the completed acquisitions.

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	9 Months Ended
	Sep. 30, 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 operating segment is as follows: December 31, Acquisitions Business Combination Adjustments September 30, Eastern $ 73,893 $ 774 $ — $ 74,667 Western 285,056 — 704 285,760 Mid-Atlantic 332,247 169,594 946 502,787 Resource Solutions 44,474 — 188 44,662 $ 735,670 $ 170,368 $ 1,838 $ 907,876 Summaries of intangible assets by type follow: Covenants Customer Relationships Trade Names Total Balance, September 30, 2024 Intangible assets $ 71,326 $ 330,550 $ 15,295 $ 417,171 Less accumulated amortization (32,413) (101,369) (10,077) (143,859) $ 38,913 $ 229,181 $ 5,218 $ 273,312 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 was $14,043 and $38,845 during the three and nine months ended September 30, 2024, respectively, and $10,109 and $18,405 during the three and nine months ended September 30, 2023, respectively. A summary of intangible amortization expense estimated for each of the next five fiscal years following fiscal year 2023 and thereafter is estimated as follows: Estimated Future Amortization Expense as of September 30, 2024 For the remainder of the fiscal year ending December 31, 2024 $ 13,703 Fiscal year ending December 31, 2025 $ 56,077 Fiscal year ending December 31, 2026 $ 49,907 Fiscal year ending December 31, 2027 $ 44,054 Fiscal year ending December 31, 2028 $ 37,777 Thereafter $ 71,794

ACCRUED FINAL CAPPING, CLOSURE

ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE	9 Months Ended
	Sep. 30, 2024
Asset Retirement Obligation Disclosure [Abstract]
ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE	ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE 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. 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. A summary of the changes to accrued final capping, closure and post-closure liabilities follows: Nine Months Ended 2024 2023 Beginning balance $ 133,904 $ 113,678 Obligations incurred 5,230 4,023 Revision in estimates (1) 8,477 — Accretion expense 8,569 7,193 Obligations settled (2) (6,545) (7,338) Ending balance $ 149,635 $ 117,556 (1) Relates to the revision in estimates of the post-closure liability for the Town of Southbridge, Massachusetts landfill (“Southbridge Landfill”). See Note 11, Other Items and Charges for further disclosure. (2) May include amounts that are being processed through accounts payable as a part of our disbursements cycle.

DEBT

DEBT	9 Months Ended
	Sep. 30, 2024
Debt And Derivatives Disclosure [Abstract]
DEBT	DEBT A summary of debt is as follows: September 30, December 31, 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 6.740% as of September 30, 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 1.885% — — 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 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 66,164 53,066 Notes payable maturing through September 2028; bearing interest up to 8.1% 1,500 230 Principal amount of debt 1,099,664 1,054,546 Less—unamortized debt issuance costs 15,787 11,103 Debt less unamortized debt issuance costs 1,083,877 1,043,443 Less—current maturities of debt 38,368 35,781 $ 1,045,509 $ 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. 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 September 30, 2024, further advances were available under the Revolving Credit Facility in the amount of $678,500. The available amount is net of outstanding irrevocable letters of credit totaling $21,500, and as of September 30, 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 September 30, 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. Loss from Termination of Bridge Financing In the nine months ended September 30, 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 their fair value is recorded in stockholders’ equity as a component of accumulated other comprehensive 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. As of both September 30, 2024 and December 31, 2023, we had $515,000 notional amount of active interest rate derivative agreements outstanding. These agreements mature between February 2026 and June 2028 and provide that we receive interest based on Term SOFR, restricted by a 0.0% floor, and pay interest at a weighted average rate of approximately 3.6%. A summary of the effect of cash flow hedges related to derivative instruments on the consolidated balance sheets follows: Fair Value Balance Sheet Location September 30, December 31, Interest rate swaps Other current assets $ 3,011 $ 5,951 Interest rate swaps Other non-current assets 2,676 4,413 $ 5,687 $ 10,364 Interest rate swaps Other accrued liabilities $ 1,392 $ — Interest rate swaps Other long-term liabilities 10,851 11,762 $ 12,243 $ 11,762 Interest rate swaps Accumulated other comprehensive loss, net of tax $ (6,556) $ (1,398) Interest rate swaps - tax effect Accumulated other comprehensive loss, net of tax 1,872 318 $ (4,684) $ (1,080)

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Legal Proceedings In the ordinary course of our business and as the 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 $250 relating to our outstanding legal proceedings as of September 30, 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. 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. 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 the 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 September 30, 2024 range between 1.5% and 7.1%. A summary of the changes to the aggregate environmental remediation liabilities for the nine months ended September 30, 2024 and 2023 follows: Nine Months Ended 2024 2023 Beginning balance $ 5,889 $ 6,335 Accretion expense 71 75 Obligations settled (1) (440) (338) Ending balance 5,520 6,072 Less: current portion 1,607 1,799 Long-term portion $ 3,913 $ 4,273 (1) May include amounts that are being processed through accounts payable as a part of our disbursement cycle.

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	9 Months Ended
	Sep. 30, 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 received as of September 30, 2024, including underwriting discounts, commissions and offering expenses, the offering resulted in net proceeds of $496,569. The net proceeds from this offering were used to repay borrowings under our Revolving Credit Facility and are further available to fund acquisition activity and for general corporate purposes. Stock Based Compensation Shares Available For Issuance In the three months ended June 30, 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 September 30, 2024, there were 2,198 Class A common stock equivalents available for future grant under the Amended 2016 Plan. Stock Options 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 requires extensive use of accounting judgment and financial estimation, including estimates of the expected term stock option holders will retain their vested stock options before exercising them and the estimated volatility of our Class A common stock price over the expected term. A summary of stock option activity follows: Stock Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term (years) Aggregate Intrinsic Value Outstanding, December 31, 2023 129 $ 66.03 Granted — $ — Exercised — $ — Forfeited — $ — Outstanding, September 30, 2024 129 $ 66.03 6.7 $ 4,311 Exercisable, September 30, 2024 66 $ 51.26 5.3 $ 3,200 Stock-based compensation expense related to stock options was $141 and $443 during the three and nine months ended September 30, 2024, respectively, as compared to $126 and $374 during the three and nine months ended September 30, 2023, respectively. As of September 30, 2024, we had $1,665 of unrecognized stock-based compensation expense related to outstanding stock options to be recognized over a weighted average period of 3.2 years. During the three and nine months ended September 30, 2024, the aggregate intrinsic value of stock options exercised was zero dollars. Other Stock Awards Restricted stock awards, restricted stock units and performance stock units, with the exception of market-based performance 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, if applicable, the value of dividends of our Class A common stock as compared to the Russell 2000 Index over the requisite service period. Typically, 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 granted to employees vest incrementally over an identified service period, typically three years, beginning on the grant date based on continued employment. Performance stock units granted to employees, including 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, as applicable. A summary of restricted stock award, restricted stock unit and performance stock unit activity follows: Restricted Stock Awards, Restricted Stock Units, and Performance Stock Units (1) Weighted Weighted Average Remaining Contractual Term (years) Aggregate Intrinsic Value Outstanding, December 31, 2023 181 $ 84.82 Granted 104 $ 99.43 Class A Common Stock Vested (49) $ 79.39 Forfeited (4) $ 85.37 Outstanding, September 30, 2024 232 $ 92.49 2.0 $ 23,109 Unvested, September 30, 2024 406 $ 94.41 1.7 $ 40,430 (1) Performance stock unit grants, including market-based performance stock units, are included at the 100% attainment level. Attainment of the maximum performance targets and market achievements would result in the issuance of an additional 174 shares of Class A common stock currently included in unvested. Stock-based compensation expense related to restricted stock awards, restricted stock units and performance stock units was $2,338 and $6,563 during the three and nine months ended September 30, 2024, respectively, as compared to $2,112 and $6,007 during the three and nine months ended September 30, 2023, respectively. During the three and nine months ended September 30, 2024, the total fair value of other stock awards vested was $579 and $4,676, respectively. As of September 30, 2024, total unrecognized stock-based compensation expense related to outstanding restricted stock units was $6,998, which will be recognized over a weighted average period of 2.1 years. As of September 30, 2024, total expected unrecognized stock-based compensation expense related to outstanding performance stock units was $6,185, which will be recognized over a weighted average period of 1.8 years. The weighted average fair value of market-based performance stock units granted during the nine months ended September 30, 2024 was $105.35 per award, which was calculated using a Monte Carlo pricing model assuming a risk-free interest rate of 4.31% 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 $145 and $428 of stock-based compensation expense related to the Second Amended and Restated 1997 Employee Stock Purchase Plan during the three and nine months ended September 30, 2024, respectively, as compared to $120 and $318 during the three and nine months ended September 30, 2023, respectively. Accumulated Other Comprehensive Loss, Net of Tax A summary of the changes in the balances of each component of accumulated other comprehensive loss, net of tax follows: Interest Rate Swaps Balance, December 31, 2023 $ (1,080) Other comprehensive loss before reclassifications 1,741 Expense reclassified from accumulated other comprehensive loss into interest expense (6,900) Income tax benefit related to items of other comprehensive loss 1,555 Other comprehensive loss, net of tax (3,604) Balance, September 30, 2024 $ (4,684) A summary of reclassifications out of accumulated other comprehensive loss, net of tax into earnings follows: Three Months Ended Nine Months Ended 2024 2023 2024 2023 Accumulated Other Comprehensive Loss, Net of Tax Amounts Reclassified Out of Accumulated Other Comprehensive Loss, Net of Tax Affected Line Item in the Consolidated Interest rate swaps $ (2,289) $ (1,805) $ (6,900) $ (4,181) Interest expense 2,289 1,805 6,900 4,181 Income before income taxes 762 495 2,034 1,146 Provision for income taxes $ 1,527 $ 1,310 $ 4,866 $ 3,035 Net income

EARNINGS PER SHARE

EARNINGS PER SHARE	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE Basic earnings per share is computed by dividing net income by the weighted average number of common shares outstanding during the period. Diluted earnings per share is calculated based on the combined weighted average number of common shares and potentially dilutive shares, which include the assumed exercise of employee stock options, unvested restricted stock awards, unvested restricted stock units and unvested performance stock units, including market-based performance units based on the expected achievement of performance targets. In computing diluted earnings per share, we utilize the treasury stock method. A summary of the numerator and denominators used in the computation of earnings per share follows: Three Months Ended Nine Months Ended 2024 2023 2024 2023 Numerator: Net income $ 5,771 $ 18,172 $ 8,660 $ 27,210 Denominators: Number of shares outstanding, end of period: Class A common stock 62,325 56,994 62,325 56,994 Class B common stock 988 988 988 988 Effect of weighted average shares outstanding (1) (4,505) (20) (4,995) (3,754) Basic weighted average common shares outstanding 58,808 57,962 58,318 54,228 Impact of potentially dilutive securities: Dilutive effect of stock options and other stock awards 113 100 97 97 Diluted weighted average common shares outstanding 58,921 58,062 58,415 54,325 Anti-dilutive potentially issuable shares 7 78 24 75 (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 9, Stockholders’ Equity for disclosure regarding the public offering of Class A common stock completed September 19, 2024.

OTHER ITEMS AND CHARGES

OTHER ITEMS AND CHARGES	9 Months Ended
	Sep. 30, 2024
Unusual or Infrequent Items, or Both [Abstract]
OTHER ITEMS AND CHARGES	OTHER ITEMS AND CHARGES Expense from Acquisition Activities In the three and nine months ended September 30, 2024, we recorded charges of $5,450 and $18,297, respectively, and in the three and nine months ended September 30, 2023, we recorded charges of $3,261 and $9,801, respectively, comprised primarily of legal, consulting, rebranding and other costs associated with the due diligence, acquisition and integration of acquired businesses. The nine months ended September 30, 2024 included 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. 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 it reached its final capacity. In both the three and nine months ended September 30, 2024, we recorded a non-cash charge of $8,477, which is 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. Legal Settlement In the nine months ended September 30, 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 the nine months ended September 30, 2024.

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS	9 Months Ended
	Sep. 30, 2024
Related Party Transactions [Abstract]
RELATED PARTY TRANSACTIONS	RELATED PARTY TRANSACTIONS Leases In the nine months ended September 30, 2024, we extended the lease related to our corporate headquarters in Rutland, Vermont through February 2039 and the lease associated with our Montpelier, Vermont facility through May 2039. Both facilities are leased from 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 terms of the lease agreements require a monthly payment of approximately $34, subject to a fixed annual escalation.

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	9 Months Ended
	Sep. 30, 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 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 and cash equivalents, accounts receivable and trade payables approximate their respective fair values due to their short-term nature. The fair value of restricted investment securities held in trust, which are valued using quoted market prices, are included as restricted assets in the Level 1 tier below. The fair value of the 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. Recurring Fair Value Measurements Summaries of our financial assets and liabilities that are measured at fair value on a recurring basis follow: Fair Value Measurement at September 30, 2024 Using: Quoted Prices in Significant Other Significant Assets: Restricted investment securities - landfill closure $ 2,422 $ — $ — Interest rate swaps — 5,687 — $ 2,422 $ 5,687 $ — Liabilities: Interest rate swaps $ — $ 12,243 $ — Fair Value Measurement at December 31, 2023 Using: Quoted Prices in Significant Other Significant Assets: Restricted investment securities - landfill closure $ 2,203 $ — $ — Interest rate swaps — 10,364 — $ 2,203 $ 10,364 $ — Liabilities: Interest rate swaps $ — $ 11,762 $ — Fair Value of Debt As of September 30, 2024, the fair value of our fixed rate debt, including our FAME Bonds 2005R-3, FAME Bonds 2015R-1, FAME Bonds 2015R-2, Vermont Bonds 2013, Vermont Bonds 2022A-1, New York Bonds 2014R-1, New York Bonds 2014R-2, New York Bonds 2020, New York Bonds 2020R-2 and New Hampshire Bonds (collectively, the “Industrial Revenue Bonds”) was approximately $232,547 and the carrying value was $232,000. The fair value of the Industrial Revenue Bonds is considered to be Level 2 within the fair value hierarchy as the fair value is determined using market approach pricing provided by a third-party that utilizes pricing models and pricing systems, mathematical tools and judgment to determine the evaluated price for the security based on the market information of each of the bonds or securities with similar characteristics. As of September 30, 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.

SEGMENT REPORTING

SEGMENT REPORTING	9 Months Ended
	Sep. 30, 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 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 services, landfill gas-to-energy services, and processing services in the eastern United States. Our Resource Solutions operating segment leverages our core competencies in materials processing, industrial recycling, organics and resource management service offerings to deliver a comprehensive solution for our larger commercial, municipal, institutional and industrial customers that have more diverse waste and recycling needs. Revenues associated with our Resource Solutions operations are comprised of processing services and non-processing services, which we refer to as our National Accounts business. Revenues from processing services are derived from customers in the form of processing fees, tipping fees, commodity sales, and organic material sales. Revenues from our National Accounts business are derived from brokerage services and overall resource management services providing a wide range of environmental services and resource management solutions to large and complex organizations, as well as traditional collection, disposal and recycling services provided to large account multi-site customers. Legal, tax, information technology, human resources, certain finance and accounting and other administrative functions are included in our Corporate Entities segment, which is not a reportable operating segment. Corporate Entities results reflect those costs not allocated to our reportable operating segments. Three Months Ended September 30, 2024 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 110,404 $ 28,836 $ 14,466 $ 5,593 $ 437,890 Western 150,756 53,891 25,523 19,654 1,006,158 Mid-Atlantic 64,005 654 13,776 (5,109) 837,855 Resource Solutions 86,462 2,981 4,472 5,545 255,160 Corporate Entities — — 937 (1,304) 586,166 Eliminations — (86,362) — — — $ 411,627 $ — $ 59,174 $ 24,379 $ 3,123,229 Three Months Ended September 30, 2023 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 97,507 $ 24,911 $ 12,381 $ 11,160 $ 417,138 Western 136,019 46,307 20,976 20,462 986,659 Mid-Atlantic (1) 43,722 212 10,182 (747) 557,710 Resource Solutions 75,487 4,172 3,452 4,110 242,413 Corporate Entities — — 745 (797) 294,095 Eliminations — (75,602) — — — $ 352,735 $ — $ 47,736 $ 34,188 $ 2,498,015 Nine Months Ended September 30, 2024 Segment Outside Inter-company Depreciation and Operating Total assets Eastern $ 310,899 $ 77,746 $ 41,950 $ 19,757 $ 437,890 Western 426,127 153,736 75,560 46,331 1,006,158 Mid-Atlantic 148,020 1,243 34,338 (16,989) 837,855 Resource Solutions 244,751 8,940 13,806 11,207 255,160 Corporate Entities — — 2,895 (6,074) 586,166 Eliminations — (241,665) — — — Total $ 1,129,797 $ — $ 168,549 $ 54,232 $ 3,123,229 Nine Months Ended September 30, 2023 Segment Outside Inter-company Depreciation and Operating Total assets Eastern $ 274,740 $ 67,843 $ 36,431 $ 20,819 $ 417,138 Western 371,281 125,208 57,559 51,880 986,659 Mid-Atlantic (1) 43,722 212 10,182 (747) 557,710 Resource Solutions 215,232 10,975 9,618 2,854 242,413 Corporate Entities — — 2,305 (7,739) 294,095 Eliminations — (204,238) — — — Total $ 904,975 $ — $ 116,095 $ 67,067 $ 2,498,015 (1) Operations under the Mid-Atlantic region commenced July 1, 2023. A summary of our revenues attributable to services provided follows: Three Months Ended Nine Months Ended 2024 2023 2024 2023 Collection $ 252,579 $ 206,093 $ 687,896 $ 495,917 Disposal 67,453 66,337 182,716 181,433 Landfill gas-to-energy 1,651 1,797 6,144 5,042 Processing 3,482 3,021 8,290 7,351 Solid waste operations 325,165 277,248 885,046 689,743 Processing 34,954 27,782 97,992 75,970 National Accounts 51,508 47,705 146,759 139,262 Resource Solutions operations 86,462 75,487 244,751 215,232 Total revenues $ 411,627 $ 352,735 $ 1,129,797 $ 904,975

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net income	$ 5,771	$ 7,006	$ (4,117)	$ 18,172	$ 5,490	$ 3,548	$ 8,660	$ 27,210

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

ACCOUNTING CHANGES (Policies)

ACCOUNTING CHANGES (Policies)	9 Months Ended
	Sep. 30, 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 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 unaudited 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. Our significant accounting policies are more fully discussed in Item 8. “ Financial Statements and Supplementary Data ” of our Annual Report on Form 10-K for the fiscal year ended December 31, 2023 (“fiscal year 2023”), which was filed with the SEC on February 16, 2024 (“2023 Form 10-K”).
Use of Estimates	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 the opinion of management, these consolidated financial statements include all adjustments, including normal recurring and nonrecurring adjustments, as applicable, necessary for a fair statement of the financial position, results of operations and cash flows for the periods presented. The results for the three and nine months ended September 30, 2024 may not be indicative of the results for any other interim period or the entire fiscal year.
Subsequent Events	We have evaluated subsequent events or transactions that have occurred after the consolidated balance sheet date of September 30, 2024 through the date of filing of the consolidated financial statements with the SEC on this Quarterly Report on Form 10-Q. Except as disclosed, no material subsequent events have occurred since September 30, 2024 through the date of this filing that would require recognition or adjustments to our disclosures in our consolidated financial statements.
Accounting Standards Adopted and Pending Adoption	The following table provides a brief description of Accounting Standards Updates (“ASU”) to the Accounting Standards Codification (“ASC”) issued by the Financial Accounting Standards Board (“FASB”) 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 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 do not expect the adoption of this guidance to have a material impact on our consolidated financial statements, however, the adoption of this guidance will have an impact on reportable operating segment disclosures within the accompanying notes to our consolidated financial statements. This guidance does not change how we identify our operating segments, aggregate them or apply quantitative thresholds to determine our reportable segments. This guidance is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. ASU No. 2023-09: Improvements to Income Tax Disclosures (Topic 740) Requires entities to provide additional disclosure related to the transparency and decision usefulness of income tax disclosures, including additional disclosure around the rate reconciliation and income taxes paid. We do not expect the adoption of this guidance to have a material impact on our consolidated financial statements, however, the adoption of this guidance will have an impact on income tax disclosures within the accompanying notes to our consolidated financial statements. This guidance is effective for fiscal years beginning after December 15, 2024, with early adoption permitted.
Accrued Final Capping, Closure and Post Closure	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. 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.
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 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 and cash equivalents, accounts receivable and trade payables approximate their respective fair values due to their short-term nature. The fair value of restricted investment securities held in trust, which are valued using quoted market prices, are included as restricted assets in the Level 1 tier below. The fair value of the 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.
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 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 services, landfill gas-to-energy services, and processing services in the eastern United States. Our Resource Solutions operating segment leverages our core competencies in materials processing, industrial recycling, organics and resource management service offerings to deliver a comprehensive solution for our larger commercial, municipal, institutional and industrial customers that have more diverse waste and recycling needs. Revenues associated with our Resource Solutions operations are comprised of processing services and non-processing services, which we refer to as our National Accounts business. Revenues from processing services are derived from customers in the form of processing fees, tipping fees, commodity sales, and organic material sales. Revenues from our National Accounts business are derived from brokerage services and overall resource management services providing a wide range of environmental services and resource management solutions to large and complex organizations, as well as traditional collection, disposal and recycling services provided to large account multi-site customers. Legal, tax, information technology, human resources, certain finance and accounting and other administrative functions are included in our Corporate Entities segment, which is not a reportable operating segment. Corporate Entities results reflect those costs not allocated to our reportable operating segments.

ACCOUNTING CHANGES (Tables)

ACCOUNTING CHANGES (Tables)	9 Months Ended
	Sep. 30, 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 Accounting Standards Updates (“ASU”) to the Accounting Standards Codification (“ASC”) issued by the Financial Accounting Standards Board (“FASB”) 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 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 do not expect the adoption of this guidance to have a material impact on our consolidated financial statements, however, the adoption of this guidance will have an impact on reportable operating segment disclosures within the accompanying notes to our consolidated financial statements. This guidance does not change how we identify our operating segments, aggregate them or apply quantitative thresholds to determine our reportable segments. This guidance is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. ASU No. 2023-09: Improvements to Income Tax Disclosures (Topic 740) Requires entities to provide additional disclosure related to the transparency and decision usefulness of income tax disclosures, including additional disclosure around the rate reconciliation and income taxes paid. We do not expect the adoption of this guidance to have a material impact on our consolidated financial statements, however, the adoption of this guidance will have an impact on income tax disclosures within the accompanying notes to our consolidated financial statements. This guidance is effective for fiscal years beginning after December 15, 2024, with early adoption permitted.

REVENUE RECOGNITION (Tables)

REVENUE RECOGNITION (Tables)	9 Months Ended
	Sep. 30, 2024
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	The following tables set forth revenues disaggregated by service line and timing of revenue recognition by operating segment for each of the three and nine months ended September 30, 2024 and 2023: Three Months Ended September 30, 2024 Eastern Western Mid-Atlantic Resource Solutions Total Revenues Collection $ 79,291 $ 109,740 $ 63,548 $ — $ 252,579 Landfill 7,745 18,019 — — 25,764 Transfer station 18,862 16,890 457 — 36,209 Transportation 1,363 4,117 — — 5,480 Landfill gas-to-energy 301 1,350 — — 1,651 Processing 2,842 640 — 34,954 38,436 National Accounts — — — 51,508 51,508 Total revenues $ 110,404 $ 150,756 $ 64,005 $ 86,462 $ 411,627 Transferred at a point-in-time $ 122 $ 645 $ — $ 16,588 $ 17,355 Transferred over time 110,282 150,111 64,005 69,874 394,272 Total revenues $ 110,404 $ 150,756 $ 64,005 $ 86,462 $ 411,627 Three Months Ended September 30, 2023 Eastern Western Mid-Atlantic (1) Resource Solutions Total Revenues Collection $ 68,944 $ 93,924 $ 43,225 $ — $ 206,093 Landfill 7,588 18,563 — — 26,151 Transfer station 16,963 17,491 497 — 34,951 Transportation 1,328 3,907 — — 5,235 Landfill gas-to-energy 208 1,589 — — 1,797 Processing 2,476 545 — 27,782 30,803 National Accounts — — — 47,705 47,705 Total revenues $ 97,507 $ 136,019 $ 43,722 $ 75,487 $ 352,735 Transferred at a point-in-time $ 121 $ 651 $ — $ 8,549 $ 9,321 Transferred over time 97,386 135,368 43,722 66,938 343,414 Total revenues $ 97,507 $ 136,019 $ 43,722 $ 75,487 $ 352,735 Nine Months Ended September 30, 2024 Eastern Western Mid-Atlantic Resource Solutions Total Revenues Collection $ 225,622 $ 315,546 $ 146,728 $ — $ 687,896 Landfill 21,940 48,156 — — 70,096 Transfer station 51,626 45,111 1,292 — 98,029 Transportation 4,071 10,520 — — 14,591 Landfill gas-to-energy 1,298 4,846 — — 6,144 Processing 6,342 1,948 — 97,992 106,282 National Accounts — — — 146,759 146,759 Total revenues $ 310,899 $ 426,127 $ 148,020 $ 244,751 $ 1,129,797 Transferred at a point-in-time $ 361 $ 1,940 $ — $ 44,304 $ 46,605 Transferred over time 310,538 424,187 148,020 200,447 1,083,192 Total revenues $ 310,899 $ 426,127 $ 148,020 $ 244,751 $ 1,129,797 Nine Months Ended September 30, 2023 Eastern Western Mid-Atlantic (1) Resource Solutions Total Revenues Collection $ 194,801 $ 257,891 $ 43,225 $ — $ 495,917 Landfill 21,109 53,943 — — 75,052 Transfer station 48,643 42,181 497 — 91,321 Transportation 3,718 11,342 — — 15,060 Landfill gas-to-energy 594 4,448 — — 5,042 Processing 5,875 1,476 — 75,970 83,321 National Accounts — — — 139,262 139,262 Total revenues $ 274,740 $ 371,281 $ 43,722 $ 215,232 $ 904,975 Transferred at a point-in-time $ 339 $ 2,072 $ — $ 23,121 $ 25,532 Transferred over time 274,401 369,209 43,722 192,111 879,443 Total revenues $ 274,740 $ 371,281 $ 43,722 $ 215,232 $ 904,975 (1) Operations under the Mid-Atlantic region commenced July 1, 2023.

BUSINESS COMBINATIONS (Tables)

BUSINESS COMBINATIONS (Tables)	9 Months Ended
	Sep. 30, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]
Schedule of Purchase Price Paid for Acquisitions	A summary of the purchase price and the purchase price allocation for acquisitions follows: Nine Months Ended 2024 2023 Purchase Price: Cash used in acquisitions, net of cash acquired $ 261,235 $ 842,635 Working capital settlements (2,633) — Holdbacks and additional consideration owed 1,575 2,435 Total consideration $ 260,177 $ 845,070 Allocated as follows: Current assets $ 7,309 $ 19,297 Property, plant and equipment: Land 1,310 6,760 Buildings and improvements 1,004 29,636 Machinery and equipment 56,396 175,309 Operating lease right-of-use assets 5,222 11,732 Intangible assets: Trade names 1,970 — Covenants not-to-compete 10,754 37,648 Customer relationships 57,713 145,553 Deferred tax liability (23,509) (11,013) Current liabilities (23,268) (21,724) Operating lease liabilities, less current portion (5,092) (9,939) Other long-term liabilities — (828) Fair value of assets acquired and liabilities assumed 89,809 382,431 Excess purchase price allocated to goodwill $ 170,368 $ 462,639
Schedule of Unaudited Pro forma Combined Information	Unaudited pro forma combined operational results prepared as though each acquisition completed since the beginning of the prior fiscal year had occurred as of January 1, 2023 is as follows: Three Months Ended Nine Months Ended 2024 2023 2024 2023 Revenues $ 419,593 $ 400,081 $ 1,195,575 $ 1,164,131 Operating income $ 23,891 $ 33,298 $ 51,151 $ 72,018 Net income $ 5,481 $ 16,765 $ 5,961 $ 26,723 Basic earnings per share attributable to common stockholders: Weighted average common shares outstanding 58,808 57,962 58,318 54,228 Basic earnings per common share $ 0.09 $ 0.29 $ 0.10 $ 0.49 Diluted earnings per share attributable to common stockholders: Weighted average common shares outstanding 58,921 58,062 58,415 54,325 Diluted earnings per common share $ 0.09 $ 0.29 $ 0.10 $ 0.49

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	9 Months Ended
	Sep. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill Activity	A summary of the activity and balances related to goodwill by operating segment is as follows: December 31, Acquisitions Business Combination Adjustments September 30, Eastern $ 73,893 $ 774 $ — $ 74,667 Western 285,056 — 704 285,760 Mid-Atlantic 332,247 169,594 946 502,787 Resource Solutions 44,474 — 188 44,662 $ 735,670 $ 170,368 $ 1,838 $ 907,876
Schedule of Intangible Assets by Type	Summaries of intangible assets by type follow: Covenants Customer Relationships Trade Names Total Balance, September 30, 2024 Intangible assets $ 71,326 $ 330,550 $ 15,295 $ 417,171 Less accumulated amortization (32,413) (101,369) (10,077) (143,859) $ 38,913 $ 229,181 $ 5,218 $ 273,312 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	A summary of intangible amortization expense estimated for each of the next five fiscal years following fiscal year 2023 and thereafter is estimated as follows: Estimated Future Amortization Expense as of September 30, 2024 For the remainder of the fiscal year ending December 31, 2024 $ 13,703 Fiscal year ending December 31, 2025 $ 56,077 Fiscal year ending December 31, 2026 $ 49,907 Fiscal year ending December 31, 2027 $ 44,054 Fiscal year ending December 31, 2028 $ 37,777 Thereafter $ 71,794

ACCRUED FINAL CAPPING, CLOSUR_2

ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE (Tables)	9 Months Ended
	Sep. 30, 2024
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Changes to Accrued Capping, Closure and Post-Closure Liabilities	A summary of the changes to accrued final capping, closure and post-closure liabilities follows: Nine Months Ended 2024 2023 Beginning balance $ 133,904 $ 113,678 Obligations incurred 5,230 4,023 Revision in estimates (1) 8,477 — Accretion expense 8,569 7,193 Obligations settled (2) (6,545) (7,338) Ending balance $ 149,635 $ 117,556 (1) Relates to the revision in estimates of the post-closure liability for the Town of Southbridge, Massachusetts landfill (“Southbridge Landfill”). See Note 11, Other Items and Charges for further disclosure. (2) May include amounts that are being processed through accounts payable as a part of our disbursements cycle.

DEBT (Tables)

DEBT (Tables)	9 Months Ended
	Sep. 30, 2024
Debt And Derivatives Disclosure [Abstract]
Schedule of Debt	A summary of debt is as follows: September 30, December 31, 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 6.740% as of September 30, 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 1.885% — — 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 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 66,164 53,066 Notes payable maturing through September 2028; bearing interest up to 8.1% 1,500 230 Principal amount of debt 1,099,664 1,054,546 Less—unamortized debt issuance costs 15,787 11,103 Debt less unamortized debt issuance costs 1,083,877 1,043,443 Less—current maturities of debt 38,368 35,781 $ 1,045,509 $ 1,007,662 Term SOFR Loans Base Rate Loans Credit Facility 1.300% to 2.175% 0.300% to 1.175%
Schedule of Cash Flow Hedges	A summary of the effect of cash flow hedges related to derivative instruments on the consolidated balance sheets follows: Fair Value Balance Sheet Location September 30, December 31, Interest rate swaps Other current assets $ 3,011 $ 5,951 Interest rate swaps Other non-current assets 2,676 4,413 $ 5,687 $ 10,364 Interest rate swaps Other accrued liabilities $ 1,392 $ — Interest rate swaps Other long-term liabilities 10,851 11,762 $ 12,243 $ 11,762 Interest rate swaps Accumulated other comprehensive loss, net of tax $ (6,556) $ (1,398) Interest rate swaps - tax effect Accumulated other comprehensive loss, net of tax 1,872 318 $ (4,684) $ (1,080)

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Schedule of Environmental Liability	A summary of the changes to the aggregate environmental remediation liabilities for the nine months ended September 30, 2024 and 2023 follows: Nine Months Ended 2024 2023 Beginning balance $ 5,889 $ 6,335 Accretion expense 71 75 Obligations settled (1) (440) (338) Ending balance 5,520 6,072 Less: current portion 1,607 1,799 Long-term portion $ 3,913 $ 4,273 (1) May include amounts that are being processed through accounts payable as a part of our disbursement cycle.

STOCKHOLDERS' EQUITY (Tables)

STOCKHOLDERS' EQUITY (Tables)	9 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Schedule of Stock Option Activity	A summary of stock option activity follows: Stock Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term (years) Aggregate Intrinsic Value Outstanding, December 31, 2023 129 $ 66.03 Granted — $ — Exercised — $ — Forfeited — $ — Outstanding, September 30, 2024 129 $ 66.03 6.7 $ 4,311 Exercisable, September 30, 2024 66 $ 51.26 5.3 $ 3,200
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 follows: Restricted Stock Awards, Restricted Stock Units, and Performance Stock Units (1) Weighted Weighted Average Remaining Contractual Term (years) Aggregate Intrinsic Value Outstanding, December 31, 2023 181 $ 84.82 Granted 104 $ 99.43 Class A Common Stock Vested (49) $ 79.39 Forfeited (4) $ 85.37 Outstanding, September 30, 2024 232 $ 92.49 2.0 $ 23,109 Unvested, September 30, 2024 406 $ 94.41 1.7 $ 40,430 (1) Performance stock unit grants, including market-based performance stock units, are included at the 100% attainment level. Attainment of the maximum performance targets and market achievements would result in the issuance of an additional 174 shares of Class A common stock currently included in unvested.
Schedule of Changes in Balances of Each Component of Accumulated Other Comprehensive Loss, Net of Tax	A summary of the changes in the balances of each component of accumulated other comprehensive loss, net of tax follows: Interest Rate Swaps Balance, December 31, 2023 $ (1,080) Other comprehensive loss before reclassifications 1,741 Expense reclassified from accumulated other comprehensive loss into interest expense (6,900) Income tax benefit related to items of other comprehensive loss 1,555 Other comprehensive loss, net of tax (3,604) Balance, September 30, 2024 $ (4,684)
Schedule of Reclassifications Out of Accumulated Other Comprehensive Loss, Net of Tax	A summary of reclassifications out of accumulated other comprehensive loss, net of tax into earnings follows: Three Months Ended Nine Months Ended 2024 2023 2024 2023 Accumulated Other Comprehensive Loss, Net of Tax Amounts Reclassified Out of Accumulated Other Comprehensive Loss, Net of Tax Affected Line Item in the Consolidated Interest rate swaps $ (2,289) $ (1,805) $ (6,900) $ (4,181) Interest expense 2,289 1,805 6,900 4,181 Income before income taxes 762 495 2,034 1,146 Provision for income taxes $ 1,527 $ 1,310 $ 4,866 $ 3,035 Net income

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	9 Months Ended
	Sep. 30, 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 follows: Three Months Ended Nine Months Ended 2024 2023 2024 2023 Numerator: Net income $ 5,771 $ 18,172 $ 8,660 $ 27,210 Denominators: Number of shares outstanding, end of period: Class A common stock 62,325 56,994 62,325 56,994 Class B common stock 988 988 988 988 Effect of weighted average shares outstanding (1) (4,505) (20) (4,995) (3,754) Basic weighted average common shares outstanding 58,808 57,962 58,318 54,228 Impact of potentially dilutive securities: Dilutive effect of stock options and other stock awards 113 100 97 97 Diluted weighted average common shares outstanding 58,921 58,062 58,415 54,325 Anti-dilutive potentially issuable shares 7 78 24 75 (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 9, Stockholders’ Equity for disclosure regarding the public offering of Class A common stock completed September 19, 2024.

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	9 Months Ended
	Sep. 30, 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 follow: Fair Value Measurement at September 30, 2024 Using: Quoted Prices in Significant Other Significant Assets: Restricted investment securities - landfill closure $ 2,422 $ — $ — Interest rate swaps — 5,687 — $ 2,422 $ 5,687 $ — Liabilities: Interest rate swaps $ — $ 12,243 $ — Fair Value Measurement at December 31, 2023 Using: Quoted Prices in Significant Other Significant Assets: Restricted investment securities - landfill closure $ 2,203 $ — $ — Interest rate swaps — 10,364 — $ 2,203 $ 10,364 $ — Liabilities: Interest rate swaps $ — $ 11,762 $ —

SEGMENT REPORTING (Tables)

SEGMENT REPORTING (Tables)	9 Months Ended
	Sep. 30, 2024
Segment Reporting [Abstract]
Schedule of Segment Reporting Information by Segment	Three Months Ended September 30, 2024 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 110,404 $ 28,836 $ 14,466 $ 5,593 $ 437,890 Western 150,756 53,891 25,523 19,654 1,006,158 Mid-Atlantic 64,005 654 13,776 (5,109) 837,855 Resource Solutions 86,462 2,981 4,472 5,545 255,160 Corporate Entities — — 937 (1,304) 586,166 Eliminations — (86,362) — — — $ 411,627 $ — $ 59,174 $ 24,379 $ 3,123,229 Three Months Ended September 30, 2023 Segment Outside Inter-company Depreciation and Operating Total Eastern $ 97,507 $ 24,911 $ 12,381 $ 11,160 $ 417,138 Western 136,019 46,307 20,976 20,462 986,659 Mid-Atlantic (1) 43,722 212 10,182 (747) 557,710 Resource Solutions 75,487 4,172 3,452 4,110 242,413 Corporate Entities — — 745 (797) 294,095 Eliminations — (75,602) — — — $ 352,735 $ — $ 47,736 $ 34,188 $ 2,498,015 Nine Months Ended September 30, 2024 Segment Outside Inter-company Depreciation and Operating Total assets Eastern $ 310,899 $ 77,746 $ 41,950 $ 19,757 $ 437,890 Western 426,127 153,736 75,560 46,331 1,006,158 Mid-Atlantic 148,020 1,243 34,338 (16,989) 837,855 Resource Solutions 244,751 8,940 13,806 11,207 255,160 Corporate Entities — — 2,895 (6,074) 586,166 Eliminations — (241,665) — — — Total $ 1,129,797 $ — $ 168,549 $ 54,232 $ 3,123,229 Nine Months Ended September 30, 2023 Segment Outside Inter-company Depreciation and Operating Total assets Eastern $ 274,740 $ 67,843 $ 36,431 $ 20,819 $ 417,138 Western 371,281 125,208 57,559 51,880 986,659 Mid-Atlantic (1) 43,722 212 10,182 (747) 557,710 Resource Solutions 215,232 10,975 9,618 2,854 242,413 Corporate Entities — — 2,305 (7,739) 294,095 Eliminations — (204,238) — — — Total $ 904,975 $ — $ 116,095 $ 67,067 $ 2,498,015 (1) Operations under the Mid-Atlantic region commenced July 1, 2023.
Schedule of Revenue Attributable to Services	A summary of our revenues attributable to services provided follows: Three Months Ended Nine Months Ended 2024 2023 2024 2023 Collection $ 252,579 $ 206,093 $ 687,896 $ 495,917 Disposal 67,453 66,337 182,716 181,433 Landfill gas-to-energy 1,651 1,797 6,144 5,042 Processing 3,482 3,021 8,290 7,351 Solid waste operations 325,165 277,248 885,046 689,743 Processing 34,954 27,782 97,992 75,970 National Accounts 51,508 47,705 146,759 139,262 Resource Solutions operations 86,462 75,487 244,751 215,232 Total revenues $ 411,627 $ 352,735 $ 1,129,797 $ 904,975

BASIS OF PRESENTATION (Details)

BASIS OF PRESENTATION (Details)	Sep. 30, 2024 state
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of states in which entity operates	10

REVENUE RECOGNITION - Disaggreg

REVENUE RECOGNITION - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Total revenues	$ 411,627	$ 352,735	$ 1,129,797	$ 904,975
Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	17,355	9,321	46,605	25,532
Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	394,272	343,414	1,083,192	879,443
Collection
Disaggregation of Revenue [Line Items]
Total revenues	252,579	206,093	687,896	495,917
Landfill
Disaggregation of Revenue [Line Items]
Total revenues	25,764	26,151	70,096	75,052
Transfer station
Disaggregation of Revenue [Line Items]
Total revenues	36,209	34,951	98,029	91,321
Transportation
Disaggregation of Revenue [Line Items]
Total revenues	5,480	5,235	14,591	15,060
Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	1,651	1,797	6,144	5,042
Processing
Disaggregation of Revenue [Line Items]
Total revenues	38,436	30,803	106,282	83,321
National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	51,508	47,705	146,759	139,262
Eastern
Disaggregation of Revenue [Line Items]
Total revenues	110,404	97,507	310,899	274,740
Eastern | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	122	121	361	339
Eastern | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	110,282	97,386	310,538	274,401
Eastern | Collection
Disaggregation of Revenue [Line Items]
Total revenues	79,291	68,944	225,622	194,801
Eastern | Landfill
Disaggregation of Revenue [Line Items]
Total revenues	7,745	7,588	21,940	21,109
Eastern | Transfer station
Disaggregation of Revenue [Line Items]
Total revenues	18,862	16,963	51,626	48,643
Eastern | Transportation
Disaggregation of Revenue [Line Items]
Total revenues	1,363	1,328	4,071	3,718
Eastern | Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	301	208	1,298	594
Eastern | Processing
Disaggregation of Revenue [Line Items]
Total revenues	2,842	2,476	6,342	5,875
Eastern | National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Western
Disaggregation of Revenue [Line Items]
Total revenues	150,756	136,019	426,127	371,281
Western | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	645	651	1,940	2,072
Western | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	150,111	135,368	424,187	369,209
Western | Collection
Disaggregation of Revenue [Line Items]
Total revenues	109,740	93,924	315,546	257,891
Western | Landfill
Disaggregation of Revenue [Line Items]
Total revenues	18,019	18,563	48,156	53,943
Western | Transfer station
Disaggregation of Revenue [Line Items]
Total revenues	16,890	17,491	45,111	42,181
Western | Transportation
Disaggregation of Revenue [Line Items]
Total revenues	4,117	3,907	10,520	11,342
Western | Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	1,350	1,589	4,846	4,448
Western | Processing
Disaggregation of Revenue [Line Items]
Total revenues	640	545	1,948	1,476
Western | National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Mid-Atlantic
Disaggregation of Revenue [Line Items]
Total revenues	64,005	43,722	148,020	43,722
Mid-Atlantic | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Mid-Atlantic | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	64,005	43,722	148,020	43,722
Mid-Atlantic | Collection
Disaggregation of Revenue [Line Items]
Total revenues	63,548	43,225	146,728	43,225
Mid-Atlantic | Landfill
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Mid-Atlantic | Transfer station
Disaggregation of Revenue [Line Items]
Total revenues	457	497	1,292	497
Mid-Atlantic | Transportation
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Mid-Atlantic | Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Mid-Atlantic | Processing
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Mid-Atlantic | National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Resource Solutions
Disaggregation of Revenue [Line Items]
Total revenues	86,462	75,487	244,751	215,232
Resource Solutions | Transferred at a point-in-time
Disaggregation of Revenue [Line Items]
Total revenues	16,588	8,549	44,304	23,121
Resource Solutions | Transferred over time
Disaggregation of Revenue [Line Items]
Total revenues	69,874	66,938	200,447	192,111
Resource Solutions | Collection
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Resource Solutions | Landfill
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Resource Solutions | Transfer station
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Resource Solutions | Transportation
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Resource Solutions | Landfill gas-to-energy
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Resource Solutions | Processing
Disaggregation of Revenue [Line Items]
Total revenues	34,954	27,782	97,992	75,970
Resource Solutions | National Accounts
Disaggregation of Revenue [Line Items]
Total revenues	$ 51,508	$ 47,705	$ 146,759	$ 139,262

REVENUE RECOGNITION - Narrative

REVENUE RECOGNITION - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Rebates	$ (411,627,000)	$ (352,735,000)	$ (1,129,797,000)	$ (904,975,000)
Revenue recognized for performance obligation satisfied in previous period	0	0	0	0
Gross receivables from contracts	174,216,000		174,216,000		$ 158,931,000
Contract liabilities	47,798,000		47,798,000		$ 31,472,000
Rebate for Recycled or Returned Organic Materials
Disaggregation of Revenue [Line Items]
Rebates	$ 9,084,000	$ 4,617,000	$ 24,615,000	$ 17,575,000

BUSINESS COMBINATIONS - Narrati

BUSINESS COMBINATIONS - Narrative (Details)	9 Months Ended
	Sep. 30, 2024 business	Sep. 30, 2023 business subsidiary
Business Acquisition [Line Items]
Number of businesses acquired	5	5
Number of wholly owned subsidiaries acquired | subsidiary		4
Minimum
Business Acquisition [Line Items]
Useful life of finite lived intangible assets	2 years
Maximum
Business Acquisition [Line Items]
Useful life of finite lived intangible assets	10 years
Solid-waste collection businesses
Business Acquisition [Line Items]
Number of businesses acquired		3
Mid-Atlantic
Business Acquisition [Line Items]
Number of businesses acquired	3
Eastern
Business Acquisition [Line Items]
Number of businesses acquired	2

BUSINESS COMBINATIONS - Summary

BUSINESS COMBINATIONS - Summary of Purchase Price Paid for Acquisitions (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Purchase Price:
Cash used in acquisitions, net of cash acquired	$ 259,196	$ 847,763
Allocated as follows:
Excess purchase price allocated to goodwill	907,876		$ 735,670
Waste Collection Acquisitions
Purchase Price:
Cash used in acquisitions, net of cash acquired	261,235	842,635
Working capital settlements	(2,633)	0
Holdbacks and additional consideration owed	1,575	2,435
Total consideration	260,177	845,070
Allocated as follows:
Current assets	7,309	19,297
Land	1,310	6,760
Buildings and improvements	1,004	29,636
Machinery and equipment	56,396	175,309
Operating lease right-of-use assets	5,222	11,732
Deferred tax liability	(23,509)	(11,013)
Current liabilities	(23,268)	(21,724)
Operating lease liabilities, less current portion	(5,092)	(9,939)
Other long-term liabilities	0	(828)
Fair value of assets acquired and liabilities assumed	89,809	382,431
Excess purchase price allocated to goodwill	170,368	462,639
Waste Collection Acquisitions | Trade Names
Allocated as follows:
Intangible assets	1,970	0
Waste Collection Acquisitions | Covenants Not-to-Compete
Allocated as follows:
Intangible assets	10,754	37,648
Waste Collection Acquisitions | Customer Relationships
Allocated as follows:
Intangible assets	$ 57,713	$ 145,553

BUSINESS COMBINATIONS - Schedul

BUSINESS COMBINATIONS - Schedule of Unaudited Pro forma Combined Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]
Revenues	$ 419,593	$ 400,081	$ 1,195,575	$ 1,164,131
Operating income	23,891	33,298	51,151	72,018
Net income	$ 5,481	$ 16,765	$ 5,961	$ 26,723
Weighted average common shares outstanding, basic (in shares)	58,808	57,962	58,318	54,228
Basic earnings per common share (in dollars per share)	$ 0.09	$ 0.29	$ 0.10	$ 0.49
Weighted average common shares outstanding, diluted (in shares)	58,921	58,062	58,415	54,325
Diluted earnings per common share (in dollars per share)	$ 0.09	$ 0.29	$ 0.10	$ 0.49

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS - Summary of Goodwill Activity (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 735,670
Acquisitions	170,368
Business Combination Adjustments	1,838
Goodwill, ending balance	907,876
Eastern
Goodwill [Roll Forward]
Goodwill, beginning balance	73,893
Acquisitions	774
Business Combination Adjustments	0
Goodwill, ending balance	74,667
Western
Goodwill [Roll Forward]
Goodwill, beginning balance	285,056
Acquisitions	0
Business Combination Adjustments	704
Goodwill, ending balance	285,760
Mid-Atlantic
Goodwill [Roll Forward]
Goodwill, beginning balance	332,247
Acquisitions	169,594
Business Combination Adjustments	946
Goodwill, ending balance	502,787
Resource Solutions
Goodwill [Roll Forward]
Goodwill, beginning balance	44,474
Acquisitions	0
Business Combination Adjustments	188
Goodwill, ending balance	$ 44,662

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS - Summary of Intangible Assets by Type (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 417,171	$ 347,469
Less accumulated amortization	(143,859)	(106,040)
Intangible assets, net	273,312	241,429
Covenants Not-to-Compete
Finite-Lived Intangible Assets [Line Items]
Intangible assets	71,326	61,573
Less accumulated amortization	(32,413)	(26,645)
Intangible assets, net	38,913	34,928
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets	330,550	272,571
Less accumulated amortization	(101,369)	(72,227)
Intangible assets, net	229,181	200,344
Trade Names
Finite-Lived Intangible Assets [Line Items]
Intangible assets	15,295	13,325
Less accumulated amortization	(10,077)	(7,168)
Intangible assets, net	$ 5,218	$ 6,157

GOODWILL AND INTANGIBLE ASSET_4

GOODWILL AND INTANGIBLE ASSETS - Narrative (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible amortization expense	$ 14,043	$ 10,109	$ 38,845	$ 18,405

GOODWILL AND INTANGIBLE ASSET_5

GOODWILL AND INTANGIBLE ASSETS - Summary of Intangible Amortization Expense Estimated (Detail) $ in Thousands	Sep. 30, 2024 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
For the remainder of the fiscal year ending December 31, 2024	$ 13,703
Fiscal year ending December 31, 2025	56,077
Fiscal year ending December 31, 2026	49,907
Fiscal year ending December 31, 2027	44,054
Fiscal year ending December 31, 2028	37,777
Thereafter	$ 71,794

ACCRUED FINAL CAPPING, CLOSUR_3

ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE - Summary of Changes to Accrued Capping, Closure and Post-Closure Liabilities (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 133,904	$ 113,678
Obligations incurred	5,230	4,023
Revision in estimates	8,477	0
Accretion expense	8,569	7,193
Obligations settled	(6,545)	(7,338)
Ending balance	$ 149,635	$ 117,556

DEBT - Summary of Debt (Details

DEBT - Summary of Debt (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Weighted-average discount rate - finance leases	4.50%
Finance leases maturing through December 2107; bearing interest at a weighted average of 4.5%	$ 66,164	$ 53,066
Principal amount of debt	1,099,664	1,054,546
Less—unamortized debt issuance costs	15,787	11,103
Debt less unamortized debt issuance costs	1,083,877	1,043,443
Less—current maturities of debt	38,368	35,781
Debt, less current portion	$ 1,045,509	$ 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 6.740% as of September 30, 2024
Debt Instrument [Line Items]
Stated interest rate	6.74%
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 1.885%
Debt Instrument [Line Items]
Variable rate margin	1.885%
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 | 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 | 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]
Stated interest rate	8.10%
Principal amount of debt	$ 1,500	$ 230

DEBT - Narrative - Credit Facil

DEBT - Narrative - Credit Facility (Details)	1 Months Ended
	Sep. 30, 2024 USD ($)
Line of Credit Facility [Line Items]
Letters of credit outstanding	$ 21,500,000
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	100%
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 | Revolving Credit Facility
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity	700,000,000
Letters of credit sublimit	155,000,000
Remaining capacity	$ 678,500,000
Credit Facility | Line of Credit | Letter of Credit
Line of Credit Facility [Line Items]
Fronting fee	0.25%

DEBT - Schedule of Variable Rat

DEBT - Schedule of Variable Rate Margins (Details) - Credit Facility - Line of Credit	9 Months Ended
	Sep. 30, 2024
Minimum | SOFR
Debt Instrument [Line Items]
Variable rate margin	1.30%
Minimum | Base Rate
Debt Instrument [Line Items]
Variable rate margin	0.30%
Maximum | SOFR
Debt Instrument [Line Items]
Variable rate margin	2.175%
Maximum | Base Rate
Debt Instrument [Line Items]
Variable rate margin	1.175%

DEBT - Narrative - Loss from Te

DEBT - Narrative - Loss from Termination of Bridge Financing (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Debt Instrument [Line Items]
Loss on debt modification	$ 0	$ 0	$ 0	$ 8,191
GFL Acquisition
Debt Instrument [Line Items]
Loss on debt modification				3,718
Twin Bridges Acquisition
Debt Instrument [Line Items]
Loss on debt modification				$ 4,473

DEBT - Narrative - Cash Flow He

DEBT - Narrative - Cash Flow Hedges (Details) - Interest Rate Contract - Cash Flow Hedging - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Derivative [Line Items]
Notional amount	$ 515,000	$ 515,000
Floor interest rate (as a percent)	0%
Weighted average percentage rate paid (as a percent)	3.60%

DEBT - Summary of Cash Flow Hed

DEBT - Summary of Cash Flow Hedges (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Derivatives, Fair Value [Line Items]
Accumulated other comprehensive loss, net of tax	$ (4,684)	$ (1,080)
Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross asset	5,687	10,364
Cash flow hedge derivatives, gross liability	12,243	11,762
Designated as Hedging Instrument | Interest rate swaps | Accumulated other comprehensive loss, net of tax
Derivatives, Fair Value [Line Items]
Accumulated other comprehensive income (loss), before tax	(6,556)	(1,398)
Accumulated other comprehensive income (loss), tax	1,872	318
Accumulated other comprehensive loss, net of tax	(4,684)	(1,080)
Other current assets | Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross asset	3,011	5,951
Other non-current assets | Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross asset	2,676	4,413
Other accrued liabilities | Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross liability	1,392	0
Other long-term liabilities | Designated as Hedging Instrument | Interest rate swaps
Derivatives, Fair Value [Line Items]
Cash flow hedge derivatives, gross liability	$ 10,851	$ 11,762

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Narrative (Detail) $ in Thousands	Sep. 30, 2024 USD ($)
Loss Contingencies [Line Items]
Loss contingency accrual	$ 250
Minimum
Loss Contingencies [Line Items]
Risk free interest	1.50%
Maximum
Loss Contingencies [Line Items]
Risk free interest	7.10%

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Environmental Remediation Liability (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 5,889	$ 6,335
Accretion expense	71	75
Obligations settled	(440)	(338)
Ending balance	5,520	6,072
Less: current portion	1,607	1,799
Long-term portion	$ 3,913	$ 4,273

STOCKHOLDERS' EQUITY - Narrativ

STOCKHOLDERS' EQUITY - Narrative (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands			3 Months Ended		9 Months Ended
	Sep. 19, 2024	Jun. 16, 2023	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Limited Partners' Capital Account [Line Items]
Expiration period					10 years
Unrecognized stock-based compensation, weighted average period					3 years 2 months 12 days
Fair value of stock awards vested			$ 579		$ 4,676
Stock Options
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense			141	$ 126	443	$ 374
Unrecognized stock-based compensation expense, stock options			1,665		1,665
Aggregate intrinsic value of options exercised			0		0
Restricted Stock Awards, Restricted Stock Units And Performance Stock Units
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense			2,338	2,112	$ 6,563	6,007
Restricted Stock | Non Employee Director
Limited Partners' Capital Account [Line Items]
Award vesting period					3 years
Restricted Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense			6,998		$ 6,998
Restricted Stock Unit | Non Employee Director
Limited Partners' Capital Account [Line Items]
Award service period					3 years
Performance Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation expense			6,185		$ 6,185
Market-based Performance Stock Units
Limited Partners' Capital Account [Line Items]
Weighted average fair value of market-based performance (in dollars per share)					$ 105.35
Risk-free interest rate					4.31%
Expected volatility					25.30%
Minimum
Limited Partners' Capital Account [Line Items]
Award vesting period					1 year
Maximum
Limited Partners' Capital Account [Line Items]
Award vesting period					5 years
Weighted average | Restricted Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period					2 years 1 month 6 days
Weighted average | Performance Stock Unit
Limited Partners' Capital Account [Line Items]
Unrecognized stock-based compensation, weighted average period					1 year 9 months 18 days
Amended and Restated 1997 Employee Stock Purchase Plan
Limited Partners' Capital Account [Line Items]
Stock-based compensation expense			$ 145	$ 120	$ 428	$ 318
Class A Common Stock
Limited Partners' Capital Account [Line Items]
Sale of stock, number of shares issued	5,175	6,053
Public offering price (in dollars per share)	$ 100
Sale of stock, net proceeds	$ 496,569
Common stock, authorized shares (in shares)			4,000		4,000
Class A Common Stock | Amended 2016 Plan
Limited Partners' Capital Account [Line Items]
Common stock, authorized shares (in shares)			1,750		1,750
Class A Common Stock | 2016 Plan
Limited Partners' Capital Account [Line Items]
Common stock, authorized shares (in shares)			2,250		2,250
Number of shares available for future grant (in shares)			2,198		2,198
Class A Common Stock | 2006 Incentive Plan
Limited Partners' Capital Account [Line Items]
Common stock, additional authorized shares (in shares)					2,723

STOCKHOLDERS' EQUITY - Summary

STOCKHOLDERS' EQUITY - Summary of Stock Option Activity (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($) $ / shares shares
Stock Options
Beginning balance, outstanding (in shares) | shares	129
Granted (in shares) | shares	0
Exercised (in shares) | shares	0
Forfeited (in shares) | shares	0
Ending balance, outstanding (in shares) | shares	129
Exercisable at end of period (in shares) | shares	66
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	0
Forfeited (in dollars per share) | $ / shares	0
Ending balance, outstanding (in dollars per share) | $ / shares	66.03
Exercisable at end of period (in dollars per share) | $ / shares	$ 51.26
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Outstanding contractual term	6 years 8 months 12 days
Exercisable contractual term	5 years 3 months 18 days
Outstanding aggregate intrinsic value | $	$ 4,311
Exercisable aggregate intrinsic value | $	$ 3,200

STOCKHOLDERS' EQUITY - Summar_2

STOCKHOLDERS' EQUITY - Summary of Restricted Stock Awards, Restricted Stock Unit and Performance-based Stock Unit Activity (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($) $ / shares shares
Performance Stock Unit
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Percentage of attainment level (as a percent)	100%
Performance Stock Unit | Class A Common Stock
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Number of additional shares (in shares)	174
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)	104
Forfeited (in shares)	(4)
Outstanding, end of period (in shares)	232
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 84.82
Granted (in dollars per share) | $ / shares	99.43
Forfeited (in dollars per share) | $ / shares	85.37
Outstanding at end of period (in dollars per share) | $ / shares	$ 92.49
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Contractual term (in years)	2 years
Aggregate intrinsic value | $	$ 23,109
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)	(49)
Weighted Average Grant Date Fair Value
Class A Common Stock Vested (in dollars per share) | $ / shares	$ 79.39
Unvested | Restricted Stock Awards, Restricted Stock Units And Performance Stock Units
Restricted Stock, Restricted Stock Units, and Performance Stock Units
Outstanding, end of period (in shares)	406
Weighted Average Grant Date Fair Value
Outstanding at end of period (in dollars per share) | $ / shares	$ 94.41
Weighted Average Remaining Contractual Term (years) and Aggregate Intrinsic Value
Contractual term (in years)	1 year 8 months 12 days
Aggregate intrinsic value | $	$ 40,430

STOCKHOLDERS' EQUITY - Summar_3

STOCKHOLDERS' EQUITY - Summary of Changes in Balances of Each Component of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 1,037,514	$ 1,025,924	$ 1,021,791	$ 1,008,383	$ 501,655	$ 497,900	$ 1,021,791	$ 497,900
Other comprehensive (loss) income, net of tax	(10,505)	786	6,115	1,872	1,835	(1,769)	(3,604)	1,938
Ending balance	1,531,530	$ 1,037,514	1,025,924	$ 1,030,867	$ 1,008,383	$ 501,655	1,531,530	$ 1,030,867
Accumulated other comprehensive loss, net of tax
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			$ (1,080)				(1,080)
Other comprehensive loss before reclassifications							1,741
Expense reclassified from accumulated other comprehensive loss into interest expense							(6,900)
Income tax benefit related to items of other comprehensive loss							1,555
Other comprehensive (loss) income, net of tax							(3,604)
Ending balance	$ (4,684)						$ (4,684)

STOCKHOLDERS' EQUITY - Summar_4

STOCKHOLDERS' EQUITY - Summary of Reclassifications Out of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ 15,748			$ 15,748			$ 46,951	$ 31,708
Income before income taxes	10,423			24,190			15,337	36,007
Provision for income taxes	4,652			6,018			6,677	8,797
Net income	5,771	$ 7,006	$ (4,117)	18,172	$ 5,490	$ 3,548	8,660	27,210
Accumulated other comprehensive loss, net of tax | Amounts Reclassified Out of Accumulated Other Comprehensive Loss, Net of Tax
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	2,289			1,805			6,900	4,181
Provision for income taxes	762			495			2,034	1,146
Net income	1,527			1,310			4,866	3,035
Interest rate swaps | Accumulated other comprehensive loss, net of tax | Amounts Reclassified Out of Accumulated Other Comprehensive Loss, Net of Tax
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (2,289)			$ (1,805)			$ (6,900)	$ (4,181)

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ in Thousands			3 Months Ended		9 Months Ended
	Sep. 19, 2024	Jun. 16, 2023	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Numerator:
Net income			$ 5,771	$ 18,172	$ 8,660	$ 27,210
Denominators:
Effect of weighted average shares outstanding (in shares)			(4,505,000)	(20,000)	(4,995,000)	(3,754,000)
Basic weighted average common shares outstanding (in shares)			58,808,000	57,962,000	58,318,000	54,228,000
Impact of potentially dilutive securities:
Dilutive effect of stock options and other stock awards (in shares)			113,000	100,000	97,000	97,000
Diluted weighted average common shares outstanding (in shares)			58,921,000	58,062,000	58,415,000	54,325,000
Anti-dilutive potentially issuable shares (in shares)			7,000	78,000	24,000	75,000
Class A Common Stock
Denominators:
Common stock, shares outstanding (in shares)			62,325,000	56,994,000	62,325,000	56,994,000	57,007,000
Impact of potentially dilutive securities:
Sale of stock, number of shares issued	5,175,000	6,053,000
Class B Common Stock
Denominators:
Common stock, shares outstanding (in shares)			988,000	988,000	988,000	988,000	988,000

OTHER ITEMS AND CHARGES (Detail

OTHER ITEMS AND CHARGES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Unusual or Infrequent Items, or Both [Abstract]
Expense from acquisition activities	$ 5,450	$ 3,261	$ 18,297	$ 9,801
Southbridge Landfill closure charge	8,477	70	8,477	276
Legal settlement	$ 0	$ 0	$ 0	$ 6,150

RELATED PARTY TRANSACTIONS (Det

RELATED PARTY TRANSACTIONS (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Related Party
Related Party Transaction [Line Items]
Leases monthly payments	$ 34

FAIR VALUE OF FINANCIAL INSTR_3

FAIR VALUE OF FINANCIAL INSTRUMENTS - Recurring Fair Value Measurements (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Assets:
Restricted assets	$ 2,422	$ 2,203
Derivative Asset, Statement Of Financial Position Extensible Enumeration, Not Disclosed Flag	Interest rate swaps	Interest rate swaps
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Interest rate swaps	$ 0	$ 0
Total assets	2,422	2,203
Liabilities:
Interest rate swaps	0	0
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Landfill
Assets:
Restricted assets	2,422	2,203
Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Interest rate swaps	5,687	10,364
Total assets	5,687	10,364
Liabilities:
Interest rate swaps	12,243	11,762
Recurring | Significant Other Observable Inputs (Level 2) | Landfill
Assets:
Restricted assets	0	0
Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Interest rate swaps	0	0
Total assets	0	0
Liabilities:
Interest rate swaps	0	0
Recurring | Significant Unobservable Inputs (Level 3) | Landfill
Assets:
Restricted assets	$ 0	$ 0

FAIR VALUE OF FINANCIAL INSTR_4

FAIR VALUE OF FINANCIAL INSTRUMENTS - Narrative (Detail)	Sep. 30, 2024 USD ($)
Fair Value | Fixed Rate Bonds
Debt Instrument [Line Items]
Debt, fair value	$ 232,547,000
Carrying Value | Fixed Rate Bonds
Debt Instrument [Line Items]
Debt, fair value	232,000,000
Carrying Value | Secured Debt
Debt Instrument [Line Items]
Debt, fair value	800,000,000
Carrying Value | Line of Credit
Debt Instrument [Line Items]
Debt, fair value	$ 0

SEGMENT REPORTING - Summary of

SEGMENT REPORTING - Summary of Financial Information by Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Segment Reporting Information [Line Items]
Revenues	$ 411,627	$ 352,735	$ 1,129,797	$ 904,975
Depreciation and amortization	59,174	47,736	168,549	116,095
Operating income (loss)	24,379	34,188	54,232	67,067
Total assets	3,123,229	2,498,015	3,123,229	2,498,015	$ 2,535,470
Operating | Eastern
Segment Reporting Information [Line Items]
Revenues	110,404	97,507	310,899	274,740
Depreciation and amortization	14,466	12,381	41,950	36,431
Operating income (loss)	5,593	11,160	19,757	20,819
Total assets	437,890	417,138	437,890	417,138
Operating | Western
Segment Reporting Information [Line Items]
Revenues	150,756	136,019	426,127	371,281
Depreciation and amortization	25,523	20,976	75,560	57,559
Operating income (loss)	19,654	20,462	46,331	51,880
Total assets	1,006,158	986,659	1,006,158	986,659
Operating | Mid-Atlantic
Segment Reporting Information [Line Items]
Revenues	64,005	43,722	148,020	43,722
Depreciation and amortization	13,776	10,182	34,338	10,182
Operating income (loss)	(5,109)	(747)	(16,989)	(747)
Total assets	837,855	557,710	837,855	557,710
Operating | Resource Solutions
Segment Reporting Information [Line Items]
Revenues	86,462	75,487	244,751	215,232
Depreciation and amortization	4,472	3,452	13,806	9,618
Operating income (loss)	5,545	4,110	11,207	2,854
Total assets	255,160	242,413	255,160	242,413
Corporate Entities
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Depreciation and amortization	937	745	2,895	2,305
Operating income (loss)	(1,304)	(797)	(6,074)	(7,739)
Total assets	586,166	294,095	586,166	294,095
Inter-company revenues
Segment Reporting Information [Line Items]
Revenues	(86,362)	(75,602)	(241,665)	(204,238)
Inter-company revenues | Eastern
Segment Reporting Information [Line Items]
Revenues	(28,836)	(24,911)	(77,746)	(67,843)
Inter-company revenues | Western
Segment Reporting Information [Line Items]
Revenues	(53,891)	(46,307)	(153,736)	(125,208)
Inter-company revenues | Mid-Atlantic
Segment Reporting Information [Line Items]
Revenues	(654)	(212)	(1,243)	(212)
Inter-company revenues | Resource Solutions
Segment Reporting Information [Line Items]
Revenues	$ (2,981)	$ (4,172)	$ (8,940)	$ (10,975)

SEGMENT REPORTING - Summary o_2

SEGMENT REPORTING - Summary of Revenues Attributable to Services Provided by Company (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenue from External Customer [Line Items]
Revenues	$ 411,627	$ 352,735	$ 1,129,797	$ 904,975
Solid waste operations
Revenue from External Customer [Line Items]
Revenues	325,165	277,248	885,046	689,743
Collection
Revenue from External Customer [Line Items]
Revenues	252,579	206,093	687,896	495,917
Disposal
Revenue from External Customer [Line Items]
Revenues	67,453	66,337	182,716	181,433
Landfill gas-to-energy
Revenue from External Customer [Line Items]
Revenues	1,651	1,797	6,144	5,042
Processing
Revenue from External Customer [Line Items]
Revenues	3,482	3,021	8,290	7,351
Resource Solutions operations
Revenue from External Customer [Line Items]
Revenues	86,462	75,487	244,751	215,232
Processing
Revenue from External Customer [Line Items]
Revenues	34,954	27,782	97,992	75,970
National Accounts
Revenue from External Customer [Line Items]
Revenues	$ 51,508	$ 47,705	$ 146,759	$ 139,262