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BUSINESS COMBINATIONS - Additional Information (Details) - business	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
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
Eastern | Tuck-in Solid Waste Collection
Business Acquisition [Line Items]
Number of businesses acquired	3
Eastern | Waste Collection, Transfer and Processing Business
Business Acquisition [Line Items]
Number of businesses acquired		1
Western | Solid Waste Collection, Transfer and Recycling Business
Business Acquisition [Line Items]
Number of businesses acquired	1
Western | Solid Waste Collection
Business Acquisition [Line Items]
Number of businesses acquired		1

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

The number of businesses acquired by the entity during the period.

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