LONG-TERM DEBT - Summary of Components of Long-Term Debt and Capital Leases by Debt Instrument (Detail) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 515,992	$ 497,680
Less—unamortized discount and debt issuance costs	12,102	15,178
Long-term debt and capital leases less unamortized discount and debt issuance costs	503,890	482,502
Less—current maturities of long-term debt	1,796	4,926
Non current portion of long term debt and capital lease obligation	502,094	477,576
Revolving Credit Facility due May 2023; bearing interest at LIBOR plus 2.00%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 33,300	0
Revolving Credit Facility due May 2023; bearing interest at LIBOR plus 2.00% \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%
Refinanced Revolving Credit Facility due October 2021; bore interest at LIBOR plus 2.75%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 0	36,000
Less—unamortized discount and debt issuance costs	$ 0	3,938
Refinanced Revolving Credit Facility due October 2021; bore interest at LIBOR plus 2.75% \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	2.75%
Credit Facility
Debt Instrument [Line Items]
Less—unamortized discount and debt issuance costs	$ 7,948	0
Secured Debt \| Term Loan Facility due May 2023; bearing interest at LIBOR plus 2.00%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 350,000	0
Secured Debt \| Term Loan Facility due May 2023; bearing interest at LIBOR plus 2.00% \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%
Secured Debt \| Term Loan B Facility due October 2023; bore interest at LIBOR plus 2.50%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 0	346,500
Less—unamortized discount and debt issuance costs	0	7,392
Unamortized discount	$ 0	1,482
Secured Debt \| Term Loan B Facility due October 2023; bore interest at LIBOR plus 2.50% \| LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	2.50%
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	$ 941	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	$ 480	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	$ 559	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	$ 656	691
Debt instrument interest rate percentage	5.125%
Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2015R-2 due August 2035 - fixed rate interest period through 2025; bearing interest at 4.375%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 15,000	0
Less—unamortized discount and debt issuance costs	$ 518	0
Debt instrument interest rate percentage	4.375%
Vermont Economic Development Authority Solid Waste Disposal Long-Term Revenue Bonds Series 2013 due April 2036 - fixed rate interest period through 2028; bearing interest at 4.625%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 16,000	16,000
Less—unamortized discount and debt issuance costs	$ 628	573
Debt instrument interest rate percentage	4.625%
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	$ 372	436
Debt instrument interest rate percentage	4.00%
Capital leases maturing through December 2107; bearing interest at a weighted average of 5.52%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 8,261	5,595
Weighted average interest rate	5.52%
Notes payable maturing through June 2027; bearing interest at a weighted average of 2.90%
Debt Instrument [Line Items]
Long-term debt and capital lease	$ 2,431	$ 2,585
Weighted average interest rate	2.90%

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

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-Name Accounting Standards Codification
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