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LONG-TERM DEBT - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($) interest_rate_derviative	Apr. 30, 2018 USD ($)
Debt Instrument [Line Items]
Loss on debt extinguishment	$ 0	$ 472,000
Cash Flow Hedging | Other Current Assets
Debt Instrument [Line Items]
Derivative asset fair value	103,000
Cash Flow Hedging | Other Noncurrent Assets
Debt Instrument [Line Items]
Derivative asset fair value	$ 953,000
Cash Flow Hedging | Interest Rate Derivative
Debt Instrument [Line Items]
Interest rate derivatives entered into | interest_rate_derviative		3
Notional amount		$ 60,000,000
Weighted average percentage rate paid		1.95%
Cash Flow Hedging | Interest Rate Derivative | LIBOR
Debt Instrument [Line Items]
Floor interest rate received		1.00%
Cash Flow Hedging | Interest Rate Derivative - February 2021
Debt Instrument [Line Items]
Notional amount		$ 35,000,000
Cash Flow Hedging | Interest Rate Derivative - February 2022
Debt Instrument [Line Items]
Notional amount		25,000
Unsecured Debt | VEDA Bonds
Debt Instrument [Line Items]
Debt Instrument, interest rate during period	4.625%
Unsecured Debt | Revenue Bonds Series Two Thousand Five Rone Due Two Thousand Twenty Five
Debt Instrument [Line Items]
Aggregate principal amount		3,600,000
Unsecured Debt | Revenue Bonds Series Two Thousand Five Rtwo Due Two Thousand Twenty Five
Debt Instrument [Line Items]
Aggregate principal amount		21,400,000
Unsecured Debt | Finance Authority of Maine Solid Waste Disposal Revenue Bonds Series 2005R-3 (FAME Bonds 2005R-3)
Debt Instrument [Line Items]
Aggregate principal amount		$ 25,000,000
Debt instrument interest rate percentage		5.25%
Subsequent Event | Unsecured Debt | Finance Authority Of Maine Solid Waste Disposal Revenue Bonds Series 2015R-2
Debt Instrument [Line Items]
Aggregate principal amount			$ 15,000,000
Debt instrument interest rate percentage			4.375%
Subsequent Event | Unsecured Debt | VEDA Bonds
Debt Instrument [Line Items]
Aggregate principal amount			$ 16,000,000
Debt instrument interest rate percentage			4.75%

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Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
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-Section 13
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-SubTopic 30
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