SEGMENT REPORTING - Adjusted EBITDA and Significant Segment Expense Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Direct Revenues	$ 1,431,950	$ 1,376,695
Cost of Revenues	1,021,884	971,070
Selling, general and administrative expenses	182,847	181,868
Total Reportable Segments
Segment Reporting Information [Line Items]
Direct Revenues	1,431,853	1,376,593
Cost of Revenues	1,017,380	967,785
Selling, general and administrative expenses	111,630	114,633
Total Reportable Segment Adjusted EBITDA	302,843	294,175
Environmental Services
Segment Reporting Information [Line Items]
Direct Revenues	1,209,113	1,172,510
Cost of Revenues	839,942	812,898
Selling, general and administrative expenses	94,580	95,137
Total Reportable Segment Adjusted EBITDA	274,591	264,475
Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Direct Revenues	222,740	204,083
Cost of Revenues	177,438	154,887
Selling, general and administrative expenses	17,050	19,496
Total Reportable Segment Adjusted EBITDA	$ 28,252	$ 29,700