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BUSINESS COMBINATIONS - Additional Information (Details) $ in Thousands	1 Months Ended	9 Months Ended
	Nov. 02, 2018 USD ($) business	Sep. 30, 2018 business	Sep. 30, 2017 business
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 | Solid Waste Collection
Business Acquisition [Line Items]
Number of transfer stations acquired			1
Western | Collection Business
Business Acquisition [Line Items]
Number of transfer stations acquired		3	2
Eastern | Collection Business
Business Acquisition [Line Items]
Number of transfer stations acquired		1
Subsequent Event | Solid Waste Collection
Business Acquisition [Line Items]
Business combination, consideration | $	$ 24,000
Subsequent Event | Western | Solid Waste Collection
Business Acquisition [Line Items]
Number of transfer stations acquired	3
Subsequent Event | Eastern | Solid Waste Collection
Business Acquisition [Line Items]
Number of transfer stations acquired	1

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477

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

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