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COMMITMENTS AND CONTINGENCIES - Additional Information (Detail) $ in Thousands			1 Months Ended		12 Months Ended
	Apr. 28, 2017 USD ($)	Apr. 26, 2017 USD ($)	Apr. 30, 2011 USD ($)	May 31, 2009 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jun. 30, 2016 USD ($)	Jan. 29, 2016	Dec. 31, 2015 USD ($)	Dec. 20, 2000 a
Southbridge Landfill
Loss Contingencies [Line Items]
Environmental remediation liability						$ 6,379
Risk free interest percentage rate						2.60%
Potsdam Environmental Remediation Liability
Loss Contingencies [Line Items]
Amount of costs			$ 12,130	$ 10,219
Environmental remediation liability						$ 5,861	$ 5,866	$ 5,221		$ 5,221
Risk free interest percentage rate						1.50%
Scrap yard and solid waste transfer station (in acres) | a											25
Remediation activities, participant share percentage									15.00%
Maximum | Southbridge Landfill | Scenario, Forecast
Loss Contingencies [Line Items]
Future cash payments					$ 3,069
Notice of Intent to Sue under the Resource Conservation and Recovery Act | Maximum
Loss Contingencies [Line Items]
Amount of costs		$ 5,000
MADEP and Casella Waste System | Notice of Intent to Sue under the Resource Conservation and Recovery Act | Maximum
Loss Contingencies [Line Items]
Amount of costs		$ 10,000
21E Settlement and Water System Construction Funding Agreement | Bonds
Loss Contingencies [Line Items]
Bond period	20 years
21E Settlement and Water System Construction Funding Agreement | Bonds | Maximum
Loss Contingencies [Line Items]
Amount of costs	$ 5,000
Town of Southbridge, Massachusetts Landfill
Loss Contingencies [Line Items]
Total costs incurred						$ 3,745

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Total costs accrued as of the balance sheet date for environmental loss contingencies.

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