BUSINESS COMBINATIONS - Summary of Purchase Price Paid for Acquisitions (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Allocated as follows:
Excess purchase price allocated to goodwill	$ 130,317		$ 122,605
Transfer Stations Acquisition
Purchase Price:
Cash paid for acquisitions	18,778	$ 414
Working capital adjustment - preliminary	358	0
Holdbacks	172	46
Total	19,308	460
Allocated as follows:
Current assets	1,587	0
Building	5,578	0
Equipment	4,642	170
Intangible assets	2,700	262
Other liabilities, net	(1,276)	(9)
Deferred tax liability	(1,635)	0
Fair value of assets acquired and liabilities assumed	11,596	423
Excess purchase price allocated to goodwill	$ 7,712	$ 37