SEGMENT REPORTING - Reconciliation to Consolidated Statements of Income to Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ 215,138	$ 180,259
Reconciliation to Consolidated Statements of Operations:
Accretion of environmental liabilities	3,407	3,156
Stock-based compensation	6,018	5,712
Depreciation and amortization	84,758	84,298
Income from operations	120,955	87,093
Other income, net	(116)	(704)
Loss on early extinguishment of debt	2,362	0
Interest expense, net of interest income	20,632	25,017
Income before provision for income taxes	98,077	62,780
Operating Segments | Environmental Services
Segment Reporting Information [Line Items]
Adjusted EBITDA	228,345	183,602
Operating Segments | Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Adjusted EBITDA	41,463	51,877
Corporate
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ (54,670)	$ (55,220)