DEBT - Summary of Components of Long-Term Debt and Capital Leases by Debt Instrument (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Principal amount of debt	$ 562,010	$ 522,728
Finance leases maturing through December 2107; bearing interest at a weighted average of 4.7%	23,829	18,364
Less - unamortized debt issuance costs	8,889	9,406
Debt less unamortized debt issuance costs	553,121	513,322
Less—current maturities of debt	5,392	4,301
Debt, less current portion	$ 547,729	$ 509,021
Weighted-average discount rate - finance leases	4.70%	4.70%
Revolving line of credit facility ("Revolving Credit Facility") due May 2023; bearing interest at LIBOR plus 1.75%
Debt Instrument [Line Items]
Principal amount of debt	$ 61,000	$ 26,900
Revolving line of credit facility ("Revolving Credit Facility") due May 2023; bearing interest at LIBOR plus 1.75% \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%	1.75%
Secured Debt \| Term loan A facility ("Term Loan Facility") due May 2023; bearing interest at LIBOR plus 1.75%
Debt Instrument [Line Items]
Principal amount of debt	$ 350,000	$ 350,000
Secured Debt \| Term loan A facility ("Term Loan Facility") due May 2023; bearing interest at LIBOR plus 1.75% \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%	1.75%
Credit Facility
Debt Instrument [Line Items]
Less - unamortized debt issuance costs	$ 5,069	$ 5,478
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014 ("New York Bonds 2014") due December 2044 - fixed rate interest period through 2019; bearing interest at 2.875%
Debt Instrument [Line Items]
Principal amount of debt	25,000	25,000
Less - unamortized debt issuance costs	$ 1,051	$ 1,057
Stated interest rate	2.875%	2.875%
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]
Principal amount of debt	$ 15,000	$ 15,000
Less - unamortized debt issuance costs	$ 374	$ 390
Stated interest rate	3.125%	3.125%
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]
Principal amount of debt	$ 25,000	$ 25,000
Less - unamortized debt issuance costs	$ 411	$ 432
Stated interest rate	5.25%	5.25%
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]
Principal amount of debt	$ 15,000	$ 15,000
Less - unamortized debt issuance costs	$ 534	$ 552
Stated interest rate	5.125%	5.125%
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]
Principal amount of debt	$ 15,000	$ 15,000
Less - unamortized debt issuance costs	$ 399	$ 417
Stated interest rate	4.375%	4.375%
Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2013 ("Vermont Bonds") due April 2036 - fixed rate interest period through 2028; bearing interest at 4.625%
Debt Instrument [Line Items]
Principal amount of debt	$ 16,000	$ 16,000
Less - unamortized debt issuance costs	$ 527	$ 541
Stated interest rate	4.625%	4.625%
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]
Principal amount of debt	$ 11,000	$ 11,000
Less - unamortized debt issuance costs	$ 524	$ 539
Stated interest rate	2.95%	2.95%
Notes payable maturing through June 2027; bearing interest at a weighted average of 3.5%
Debt Instrument [Line Items]
Principal amount of debt	$ 5,181	$ 5,464
Weighted average interest rate	3.50%	3.50%

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

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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

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