REVENUES - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Total revenues	$ 5,166,605	$ 3,805,566	$ 3,144,097
Technical Services
Disaggregation of Revenue [Line Items]
Total revenues	1,495,264	1,209,624	1,062,714
Industrial Services and Other
Disaggregation of Revenue [Line Items]
Total revenues	1,311,579	706,298	480,621
Field and Emergency Response Services
Disaggregation of Revenue [Line Items]
Total revenues	575,300	466,380	461,036
Safety-Kleen Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues	962,697	805,491	809,236
Safety-Kleen Oil
Disaggregation of Revenue [Line Items]
Total revenues	821,765	617,773	330,490
United States
Disaggregation of Revenue [Line Items]
Total revenues	4,576,167	3,324,953	2,739,557
Canada
Disaggregation of Revenue [Line Items]
Total revenues	590,438	480,613	404,540
Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues	4,171,706	3,032,454	2,635,901
Safety-Kleen Sustainability Solutions
Disaggregation of Revenue [Line Items]
Total revenues	994,392	772,813	507,906
Operating segments | Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues	4,144,973	3,025,907	2,637,641
Operating segments | Environmental Services | Technical Services
Disaggregation of Revenue [Line Items]
Total revenues	1,495,264	1,209,624	1,062,714
Operating segments | Environmental Services | Industrial Services and Other
Disaggregation of Revenue [Line Items]
Total revenues	1,311,072	705,999	480,331
Operating segments | Environmental Services | Field and Emergency Response Services
Disaggregation of Revenue [Line Items]
Total revenues	575,300	466,380	461,036
Operating segments | Environmental Services | Safety-Kleen Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues	763,337	643,904	633,560
Operating segments | Environmental Services | Safety-Kleen Oil
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Operating segments | Environmental Services | United States
Disaggregation of Revenue [Line Items]
Total revenues	3,675,880	2,631,112	2,287,796
Operating segments | Environmental Services | Canada
Disaggregation of Revenue [Line Items]
Total revenues	469,093	394,795	349,845
Operating segments | Safety-Kleen Sustainability Solutions
Disaggregation of Revenue [Line Items]
Total revenues	1,021,125	779,360	506,166
Operating segments | Safety-Kleen Sustainability Solutions | Technical Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Operating segments | Safety-Kleen Sustainability Solutions | Industrial Services and Other
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Operating segments | Safety-Kleen Sustainability Solutions | Field and Emergency Response Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Operating segments | Safety-Kleen Sustainability Solutions | Safety-Kleen Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues	199,360	161,587	175,676
Operating segments | Safety-Kleen Sustainability Solutions | Safety-Kleen Oil
Disaggregation of Revenue [Line Items]
Total revenues	821,765	617,773	330,490
Operating segments | Safety-Kleen Sustainability Solutions | United States
Disaggregation of Revenue [Line Items]
Total revenues	899,780	693,542	452,435
Operating segments | Safety-Kleen Sustainability Solutions | Canada
Disaggregation of Revenue [Line Items]
Total revenues	121,345	85,818	53,731
Corporate, non-segment
Disaggregation of Revenue [Line Items]
Total revenues	507	299	290
Corporate, non-segment | Technical Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate, non-segment | Industrial Services and Other
Disaggregation of Revenue [Line Items]
Total revenues	507	299	290
Corporate, non-segment | Field and Emergency Response Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate, non-segment | Safety-Kleen Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate, non-segment | Safety-Kleen Oil
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0
Corporate, non-segment | United States
Disaggregation of Revenue [Line Items]
Total revenues	507	299	(674)
Corporate, non-segment | Canada
Disaggregation of Revenue [Line Items]
Total revenues	$ 0	$ 0	$ 964