SEGMENT REPORTING - Reconciliation of EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Net Income to Adjusted EBITDA
Net income (loss)		$ 5,337	$ (389,359)	$ 33,140
Income tax expense (benefit)		4,765	(4,242)	16,659
Interest expense		28,966	32,595	19,239
Interest income		(1,417)	(258)	(605)
Foreign currency loss		171	1,134	733
Other income		(4,476)	(788)	(455)
Property and equipment impairment charges				25
Goodwill impairment charges			404,900
Depreciation and amortization of plant and equipment		70,799	66,561	41,423
Amortization of intangibles assets		34,614	37,344	15,491
Share-based compensation		7,478	6,651	5,544
Accretion and non-cash adjustment of closure & post-closure liabilities		5,363	4,000	4,388
Gain on property insurance recoveries				(12,366)
Business development and integration expenses		3,274	11,621	26,150
Adjusted EBITDA		154,874	170,159	149,366
Field & Industrial Services
Reconciliation of Net Income to Adjusted EBITDA
Goodwill impairment charges	$ 14,400
Operating Segment | Environmental Services
Reconciliation of Net Income to Adjusted EBITDA
Adjusted EBITDA		170,953	176,702	184,133
Operating Segment | Field & Industrial Services
Reconciliation of Net Income to Adjusted EBITDA
Adjusted EBITDA		70,578	81,770	26,707
Operating Segment | Energy Waste
Reconciliation of Net Income to Adjusted EBITDA
Adjusted EBITDA		11,321	4,982	3,626
Corporate
Reconciliation of Net Income to Adjusted EBITDA
Adjusted EBITDA		$ (97,978)	$ (93,295)	$ (65,100)