SEGMENT REPORTING - Reconciliation to Consolidated Statements of Income to Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ 301,814	$ 255,017	$ 859,725	$ 757,661
Reconciliation to Consolidated Statements of Operations:
Accretion of environmental liabilities	3,618	3,388	10,139	10,281
Stock-based compensation	5,837	4,291	20,690	14,809
Depreciation and amortization	100,063	92,970	295,632	267,425
Income from operations	192,296	154,368	533,264	465,146
Other expense (income), net	1,123	(334)	2,431	833
Loss on early extinguishment of debt	0	0	0	2,362
Interest expense, net of interest income	35,779	29,696	100,767	80,400
Income before provision for income taxes	155,394	125,006	430,066	381,551
Operating Segments | Environmental Services
Segment Reporting Information [Line Items]
Adjusted EBITDA	332,502	288,982	956,892	822,949
Operating Segments | Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Adjusted EBITDA	41,226	31,146	122,402	126,024
Corporate
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ (71,914)	$ (65,111)	$ (219,569)	$ (191,312)