COMMITMENTS AND CONTINGENCIES - Additional Information (Detail)			6 Months Ended	12 Months Ended
	Jul. 17, 2018 USD ($)	Apr. 28, 2017 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)	Apr. 26, 2017 USD ($)	Jan. 29, 2016	Apr. 30, 2011 USD ($)	May 31, 2009 USD ($)	Dec. 20, 2000 a
Loss Contingencies [Line Items]
Litigation settlement, future cash payments			$ 850,000
Ancillary services, period			5 years
Litigation settlement, total cash and services			$ 1,200,000
Southbridge Landfill
Loss Contingencies [Line Items]
Risk free interest percentage rate			2.60%
Reserve for probable loss			$ 1,216,000
Potsdam Environmental Remediation Liability
Loss Contingencies [Line Items]
Risk free interest percentage rate			1.50%
Scrap yard and solid waste transfer station (in acres) | a									25
Undiscounted costs preferred remedies							$ 12,130,000	$ 10,219,000
Remediation activities, participant share percentage						15.00%
Maximum | Southbridge Landfill | Scenario, Forecast
Loss Contingencies [Line Items]
Loss on contract termination				$ 2,199,000
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		$ 5,000,000
Notice of Intent to Sue under the Resource Conservation and Recovery Act
Loss Contingencies [Line Items]
Estimate of possible loss					$ 5,000,000
Notice of Intent to Sue under the Resource Conservation and Recovery Act | MADEP and Casella Waste System
Loss Contingencies [Line Items]
Estimate of possible loss					$ 10,000,000
Steadfast Insurance Company | Subsequent Event
Loss Contingencies [Line Items]
Insurance settlement receivable	$ 10,000