SEGMENT REPORTING - Reconciliation of Third Party Revenues to Direct Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Total revenues	$ 1,363,086	$ 951,479	$ 3,888,507	$ 2,686,085
Environmental Services
Segment Reporting Information [Line Items]
Total revenues	1,086,484	745,633	3,124,672	2,124,332
Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Total revenues	276,319	205,787	763,401	561,536
Operating Segments | Environmental Services
Segment Reporting Information [Line Items]
Total revenues	1,080,032	743,831	3,105,336	2,119,856
Operating Segments | Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Total revenues	282,771	207,589	782,737	566,012
Intersegment revenues, net | Environmental Services
Segment Reporting Information [Line Items]
Total revenues	6,452	1,802	19,336	4,476
Intersegment revenues, net | Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Total revenues	(6,452)	(1,802)	(19,336)	(4,476)
Corporate
Segment Reporting Information [Line Items]
Total revenues	$ 283	$ 59	$ 434	$ 217