LONG-TERM DEBT - Summary of Components of Long-Term Debt and Capital Leases by Debt Instrument (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 514,460	$ 497,680
Less—unamortized discount and debt issuance costs	14,489	15,178
Long-term debt and capital leases less unamortized discount and debt issuance costs	499,971	482,502
Less—current maturities of long-term debt	5,037	4,926
Non current portion of long term debt and capital lease obligation	494,934	477,576
Revolving Credit Facility
Debt Instrument [Line Items]
Long-term debt and capital lease	52,600	36,000
Less—unamortized discount and debt issuance costs	$ 3,682	3,938
Basis spread on variable rate	2.75%
Secured Debt \| Term Loan B Facility due October 2023; bearing interest at LIBOR plus 2.50%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 345,625	346,500
Less—unamortized discount and debt issuance costs	$ 7,101	7,392
Basis spread on variable rate	2.50%
Unamortized discount	$ 1,424	1,482
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014 due December 2044 - fixed rate interest period through 2019; bearing interest at 3.75%
Debt Instrument [Line Items]
Long-term debt and capital lease	25,000	25,000
Less—unamortized discount and debt issuance costs	$ 987	1,034
Debt instrument interest rate percentage	3.75%
New York State Environmental Facilities Corporation Solid Waste Disposal Revenue Bonds Series 2014R-2 due December 2044 - fixed rate interest period through 2026; bearing interest at 3.125%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 15,000	15,000
Less—unamortized discount and debt issuance costs	$ 496	511
Debt instrument interest rate percentage	3.125%
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2005R-3 due January 2025 - fixed rate interest period through 2025; bearing interest at 5.25%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 25,000	25,000
Less—unamortized discount and debt issuance costs	$ 581	603
Debt instrument interest rate percentage	5.25%
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-1 due August 2035 - fixed rate interest period through 2025; bearing interest at 5.125%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 15,000	15,000
Less—unamortized discount and debt issuance costs	$ 673	691
Debt instrument interest rate percentage	5.125%
Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2013 due April 2036 - fixed rate interest period through 2018; bearing interest at 4.75%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 16,000	16,000
Less—unamortized discount and debt issuance costs	$ 565	573
Debt instrument interest rate percentage	4.75%
Business Finance Authority of the State of New Hampshire Solid Waste Disposal Revenue Bonds Series 2013 due April 2029 - fixed rate interest period through 2019; bearing interest at 4.00%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 11,000	11,000
Less—unamortized discount and debt issuance costs	$ 404	436
Debt instrument interest rate percentage	4.00%
Capital leases maturing through December 2107; bearing interest at up to 7.70%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 6,713	5,595
Debt instrument interest rate percentage	7.70%
Notes payable maturing through June 2027; bearing interest at up to 7.00%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 2,522	$ 2,585
Debt instrument interest rate percentage	7.00%

Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13,16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
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Amount, after accumulated amortization, of debt discount.

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-SubTopic 30
-Section 45
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Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer.

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