SEGMENT REPORTING - Reconciliation of Third Party Revenues to Direct Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Total revenues	$ 1,365,696	$ 1,363,086	$ 4,070,983	$ 3,888,507
Environmental Services
Segment Reporting Information [Line Items]
Total revenues	1,146,363	1,086,484	3,389,140	3,124,672
Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Total revenues	219,221	276,319	681,508	763,401
Operating Segments | Environmental Services
Segment Reporting Information [Line Items]
Total revenues	1,135,279	1,080,032	3,357,743	3,105,336
Operating Segments | Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Total revenues	230,305	282,771	712,905	782,737
Intersegment Revenues (Expenses), net | Environmental Services
Segment Reporting Information [Line Items]
Total revenues	11,084	6,452	31,397	19,336
Intersegment Revenues (Expenses), net | Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Total revenues	(11,084)	(6,452)	(31,397)	(19,336)
Corporate
Segment Reporting Information [Line Items]
Total revenues	$ 112	$ 283	$ 335	$ 434