FAIR VALUE OF FINANCIAL INSTRUMENTS - Additional Information (Detail)	Jun. 30, 2018 USD ($)
Significant Other Observable Inputs (Level 2)
Debt Instrument [Line Items]
Carrying value of revolver debt	$ 33,300,000
Finance Authority Of Maine Solid Waste Disposal Revenue Bonds Series 2015R-2 \| Unsecured Debt
Debt Instrument [Line Items]
Aggregate principal amount	15,000,000
Term Loan B Facility due October 2023; bore interest at LIBOR plus 2.50% \| Secured Debt
Debt Instrument [Line Items]
Aggregate principal amount	350,000,000
Fair Value \| Fixed Rate Bonds
Debt Instrument [Line Items]
Fair value of fixed rate debt	123,369,000
Carrying Value \| Fixed Rate Bonds
Debt Instrument [Line Items]
Fair value of fixed rate debt	122,000,000
Carrying Value \| Term Loan B Facility due October 2023; bore interest at LIBOR plus 2.50% \| Secured Debt
Debt Instrument [Line Items]
Fair value of fixed rate debt	$ 350,000,000

Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13476-108611

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Fair value portion of contractual arrangement with a lender under which borrowings can be made up to a specific amount at any point in time.

+ References

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