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BUSINESS COMBINATIONS - Narrative (Detail) - business | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Business Acquisition [Line Items] |  |  |
Number of businesses acquired | 10 | 9 | 9
Intangible assets, useful life | 10 years |  |
Minimum |  |  |
Business Acquisition [Line Items] |  |  |
Intangible assets, useful life | 5 years |  |
Maximum |  |  |
Business Acquisition [Line Items] |  |  |
Intangible assets, useful life | 10 years |  |
Western | Tuck-in Solid Waste Collection Business |  |  |
Business Acquisition [Line Items] |  |  |
Number of businesses acquired | 7 | 4 |
Western | Solid Waste Collection Business |  |  |
Business Acquisition [Line Items] |  |  |
Number of businesses acquired |  |  | 6
Western | Transfer Business |  |  |
Business Acquisition [Line Items] |  |  |
Number of businesses acquired |  |  | 1
Resource Solutions | Recycling Operation |  |  |
Business Acquisition [Line Items] |  |  |
Number of businesses acquired | 1 |  |
Eastern | Tuck-in Solid Waste Collection Business |  |  |
Business Acquisition [Line Items] |  |  |
Number of businesses acquired |  | 3 |
Eastern | Collection and Transfer Business |  |  |
Business Acquisition [Line Items] |  |  |
Number of businesses acquired |  |  | 2

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