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BUSINESS COMBINATIONS - Narrative (Details) - business	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Business Acquisition [Line Items]
Number of businesses acquired		2
Minimum
Business Acquisition [Line Items]
Useful life of finite lived intangible assets	5 years
Maximum
Business Acquisition [Line Items]
Useful life of finite lived intangible assets	10 years
Western | Tuck-in Solid Waste Collection Business
Business Acquisition [Line Items]
Number of businesses acquired	1	1
Western | Recycling Operation
Business Acquisition [Line Items]
Number of businesses acquired	1
Resource Solutions | Recycling Operation
Business Acquisition [Line Items]
Number of businesses acquired		1

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