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COMMITMENTS AND CONTINGENCIES - Environmental Remediation Liability (Details) - Southbridge Landfill - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 4,596	$ 5,173
Accretion expense	62	65
Obligations incurred	28	0
Revisions in estimates	(188)	0
Obligations settled	(293)	(392)
Ending balance	$ 4,205	$ 4,846

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

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Amount of expense for newly incurred environmental loss contingencies. Includes, but is not limited to, remediation expense and interest accretion.

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Amount of expense (reversal of expense) which increases (decreases) the accrual for environmental loss contingencies from revisions in estimates to existing obligations. Excludes changes related to business acquisitions, divestitures, or currency movement.

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Amount of cash outflow to settle environmental loss contingencies.

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