REVENUES - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,552,719	$ 1,397,900	$ 2,929,414	$ 2,705,287
Technical Services
Disaggregation of Revenue [Line Items]
Total revenues	443,668	389,908	851,159	756,417
Industrial Services and Other
Disaggregation of Revenue [Line Items]
Total revenues	359,570	399,661	719,069	736,147
Field and Emergency Response Services
Disaggregation of Revenue [Line Items]
Total revenues	252,893	154,359	416,362	302,445
Safety-Kleen Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues	299,687	280,122	583,630	539,689
Safety-Kleen Oil
Disaggregation of Revenue [Line Items]
Total revenues	196,901	173,850	359,194	370,589
United States
Disaggregation of Revenue [Line Items]
Total revenues	1,408,216	1,254,849	2,655,688	2,435,311
Canada
Disaggregation of Revenue [Line Items]
Total revenues	144,503	143,051	273,726	269,976
Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues	1,309,383	1,172,036	2,481,893	2,242,777
Safety-Kleen Sustainability Solutions
Disaggregation of Revenue [Line Items]
Total revenues	243,237	225,748	447,320	462,287
Operating Segments | Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues	1,297,298	1,161,482	2,458,577	2,222,464
Operating Segments | Environmental Services | Technical Services
Disaggregation of Revenue [Line Items]
Total revenues	443,668	389,908	851,159	756,417
Operating Segments | Environmental Services | Industrial Services and Other
Disaggregation of Revenue [Line Items]
Total revenues	359,471	399,545	718,868	735,924
Operating Segments | Environmental Services | Field and Emergency Response Services
Disaggregation of Revenue [Line Items]
Total revenues	252,893	154,359	416,362	302,445
Operating Segments | Environmental Services | Safety-Kleen Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues	241,266	217,670	472,188	427,678
Operating Segments | Environmental Services | Safety-Kleen Oil
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Environmental Services | United States
Disaggregation of Revenue [Line Items]
Total revenues	1,175,328	1,041,739	2,228,786	2,000,323
Operating Segments | Environmental Services | Canada
Disaggregation of Revenue [Line Items]
Total revenues	121,970	119,743	229,791	222,141
Operating Segments | Safety-Kleen Sustainability Solutions
Disaggregation of Revenue [Line Items]
Total revenues	255,322	236,302	470,636	482,600
Operating Segments | Safety-Kleen Sustainability Solutions | Technical Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Safety-Kleen Sustainability Solutions | Industrial Services and Other
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Safety-Kleen Sustainability Solutions | Field and Emergency Response Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Safety-Kleen Sustainability Solutions | Safety-Kleen Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues	58,421	62,452	111,442	112,011
Operating Segments | Safety-Kleen Sustainability Solutions | Safety-Kleen Oil
Disaggregation of Revenue [Line Items]
Total revenues	196,901	173,850	359,194	370,589
Operating Segments | Safety-Kleen Sustainability Solutions | United States
Disaggregation of Revenue [Line Items]
Total revenues	232,789	212,994	426,701	434,765
Operating Segments | Safety-Kleen Sustainability Solutions | Canada
Disaggregation of Revenue [Line Items]
Total revenues	22,533	23,308	43,935	47,835
Corporate
Disaggregation of Revenue [Line Items]
Total revenues	99	116	201	223
Corporate | Technical Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Corporate | Industrial Services and Other
Disaggregation of Revenue [Line Items]
Total revenues	99	116	201	223
Corporate | Field and Emergency Response Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Corporate | Safety-Kleen Environmental Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Corporate | Safety-Kleen Oil
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Corporate | United States
Disaggregation of Revenue [Line Items]
Total revenues	99	116	201	223
Corporate | Canada
Disaggregation of Revenue [Line Items]
Total revenues	$ 0	$ 0	$ 0	$ 0