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COMMITMENTS AND CONTINGENCIES - Narrative (Detail) plantiff in Thousands					12 Months Ended
	Dec. 01, 2020 USD ($)	Sep. 18, 2020 USD ($)	Sep. 17, 2019 plantiff	Apr. 28, 2017 USD ($)	Dec. 31, 2020 USD ($)	Apr. 26, 2017 USD ($)	Jan. 29, 2016	Apr. 30, 2011 USD ($)	May 31, 2009 USD ($)	Dec. 20, 2000 a
Notice of Intent to Sue under the Resource Conservation and Recovery Act
Other Commitments [Line Items]
Estimated possible loss						$ 5,000,000
Ontario County, New York Class Action Litigation
Other Commitments [Line Items]
Amount awarded to other party	$ 750,000
Estimated possible loss	$ 900,000
Number of plaintiffs | plantiff			1
Southbridge Landfill
Other Commitments [Line Items]
Risk free interest rate					2.60%
Southbridge Landfill | Citizen Groups and the Residents Litigation Case
Other Commitments [Line Items]
Amount awarded to other party		$ 2,000,000
Payments for litigation settlement					$ 2,000,000
Potsdam Environmental Remediation Liability
Other Commitments [Line Items]
Risk free interest rate					1.90%
Number of acres composing solid waste transfer station | a										25
Estimate of total undiscounted costs associated with implementing the preferred remedies								$ 12,130,000	$ 10,219,000
Remediation activities, participant share percentage							15.00%
Town of Southbridge, Massachusetts | Southbridge Landfill | Citizen Groups and the Residents Litigation Case
Other Commitments [Line Items]
Amount awarded to other party		1,000,000
Casella Waste Systems and Town of Southbridge, Massachusetts | Southbridge Landfill | Citizen Groups and the Residents Litigation Case
Other Commitments [Line Items]
Amount awarded to other party		$ 3,000,000
MADEP | Notice of Intent to Sue under the Resource Conservation and Recovery Act
Other Commitments [Line Items]
Estimated possible loss						$ 10,000,000
21E Settlement and Water System Construction Funding Agreement | Bonds
Other Commitments [Line Items]
Facility term				20 years
Anticipated costs				$ 4,089,000

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Percentage participation in onsite remediation activities.

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Total anticipated costs associated with remediation, site restoration, postclosure, monitoring commitments, or other exit costs that may occur on the sale, disposal, or abandonment of a particular property resulting from unanticipated contamination of the assets.

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