BUSINESS COMBINATIONS - Summary of Purchase Price Paid for Acquisitions (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Allocated as follows:
Excess purchase price allocated to goodwill	$ 121,700		$ 119,899
Transfer Stations Acquisition
Purchase Price:
Cash paid for acquisitions	2,664	$ 2,439
Notes payable	2,400	0
Other non-cash considerations	100	0
Holdbacks	196	400
Total	5,360	2,839
Allocated as follows:
Current assets	0	40
Land	0	353
Building	0	1,360
Equipment	2,291	269
Intangible assets	1,317	0
Other liabilities, net	(49)	(106)
Fair value of assets acquired and liabilities assumed	3,559	1,916
Excess purchase price allocated to goodwill	$ 1,801	$ 923