SEGMENT REPORTING - Reconciliation to Consolidated Statements of Income to Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ 327,816	$ 287,506	$ 557,911	$ 502,644
Reconciliation to Consolidated Statements of Operations:
Accretion of environmental liabilities	3,304	3,486	6,521	6,893
Stock-based compensation	8,515	4,500	14,853	10,518
Depreciation and amortization	100,504	89,697	195,569	174,455
Income from operations	215,493	189,823	340,968	310,778
Other expense, net	167	1,283	1,308	1,167
Loss on early extinguishment of debt	0	0	0	2,362
Interest expense, net of interest income	36,449	30,072	64,988	50,704
Income before provision for income taxes	178,877	158,468	274,672	256,545
Operating Segments | Environmental Services
Segment Reporting Information [Line Items]
Adjusted EBITDA	359,915	305,622	624,390	533,967
Operating Segments | Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Adjusted EBITDA	51,476	53,415	81,176	94,878
Corporate
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ (83,575)	$ (71,531)	$ (147,655)	$ (126,201)