DEBT - Summary of Debt (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Weighted-average discount rate - finance leases	3.70%
Finance leases maturing through December 2107; bearing interest at a weighted average of 3.7%	$ 48,800	$ 49,813
Principal amount of debt	596,116	603,477
Less - unamortized debt issuance costs	9,275	9,494
Debt less unamortized debt issuance costs	586,841	593,983
Less—current maturities of debt	9,274	8,968
Debt, less current portion	$ 577,567	$ 585,015
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Debt, less current portion	Debt, less current portion
Secured Debt \| Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at term secured overnight financing rate ("Term SOFR") plus 1.135%
Debt Instrument [Line Items]
Principal amount of debt	$ 350,000	$ 350,000
Secured Debt \| Term loan A facility ("Term Loan Facility") due December 2026; bearing interest at term secured overnight financing rate ("Term SOFR") plus 1.135% \| SOFR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	1.135%
Line of Credit \| Revolving credit facility ("Revolving Credit Facility") due December 2026; bearing interest at Term SOFR plus 1.135%
Debt Instrument [Line Items]
Principal amount of debt	$ 0	6,000
Credit Facility \| Revolving Credit Facility and Term Loan Facility (collectively, the "Credit Facility")
Debt Instrument [Line Items]
Less - unamortized debt issuance costs	$ 4,692	4,716
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 through 2029; bearing interest at 2.875%
Debt Instrument [Line Items]
Stated interest rate	2.875%
Principal amount of debt	$ 25,000	25,000
Less - unamortized debt issuance costs	$ 849	866
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 through 2026; bearing interest at 3.125%
Debt Instrument [Line Items]
Stated interest rate	3.125%
Principal amount of debt	$ 15,000	15,000
Less - unamortized debt issuance costs	$ 192	207
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 through 2025; bearing interest at 2.750%
Debt Instrument [Line Items]
Stated interest rate	2.75%
Principal amount of debt	$ 40,000	40,000
Less - unamortized debt issuance costs	$ 1,061	1,106
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 through 2025; bearing interest at 5.25%
Debt Instrument [Line Items]
Stated interest rate	5.25%
Principal amount of debt	$ 25,000	25,000
Less - unamortized debt issuance costs	$ 155	176
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 through 2025; bearing interest at 5.125%
Debt Instrument [Line Items]
Stated interest rate	5.125%
Principal amount of debt	$ 15,000	15,000
Less - unamortized debt issuance costs	$ 326	344
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 through 2025; bearing interest at 4.375%
Debt Instrument [Line Items]
Stated interest rate	4.375%
Principal amount of debt	$ 15,000	15,000
Less - unamortized debt issuance costs	$ 175	193
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 through 2028; bearing interest at 4.625%
Debt Instrument [Line Items]
Stated interest rate	4.625%
Principal amount of debt	$ 16,000	16,000
Less - unamortized debt issuance costs	$ 365	378
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 through 2027; bearing interest at 5.00%
Debt Instrument [Line Items]
Stated interest rate	5.00%
Principal amount of debt	$ 35,000	35,000
Less - unamortized debt issuance costs	$ 1,111	1,144
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 through 2029; bearing interest at 2.95%
Debt Instrument [Line Items]
Stated interest rate	2.95%
Principal amount of debt	$ 11,000	11,000
Less - unamortized debt issuance costs	$ 349	364
Notes payable maturing through August 2024; bearing interest up to 4.0%
Debt Instrument [Line Items]
Stated interest rate	4.00%
Principal amount of debt	$ 316	$ 664

Amount of short-term and long-term debt and lease obligation.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Present value of lessee's discounted obligation for lease payments from finance lease.

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Weighted average discount rate for finance lease calculated at point in time.

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Amount of long-term debt and lease obligation, classified as noncurrent.

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Amount of long-term debt and lease obligation, classified as current.

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