BUSINESS COMBINATIONS - Summary of Purchase Price Paid for Acquisitions (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Purchase Price:
Cash used in acquisitions, net of cash acquired	$ 25,379	$ 73,496
Allocated as follows:
Excess purchase price allocated to goodwill	192,379		$ 185,819
Waste Collection Acquisitions
Purchase Price:
Cash used in acquisitions, net of cash acquired	23,062	71,038
Notes payable	0	2,714
Other non-cash consideration	0	5,470
Contingent consideration and holdbacks	3,387	1,755
Total	26,449	80,977
Allocated as follows:
Current assets	227	1,935
Other non-current assets	0	367
Land	895	2,487
Buildings	1,908	5,422
Equipment	10,006	20,592
Intangible assets	7,159	31,171
Other liabilities, net	(306)	(3,040)
Deferred tax liability	0	(2,137)
Fair value of assets acquired and liabilities assumed	19,889	56,797
Excess purchase price allocated to goodwill	$ 6,560	$ 24,180