SEGMENT REPORTING - Segment Information, Revenues, EBITA, and Reconciliation to the Consolidated Statement of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total revenues	$ 3,805,566	$ 3,144,097	$ 3,412,190
Adjusted EBITDA	676,606	573,804	558,133
Reconciliation to Consolidated Statements of Operations:
Accretion of environmental liabilities	11,745	11,051	10,136
Stock-based compensation	18,839	18,502	17,816
Depreciation and amortization	298,135	292,915	300,725
Income from operations	347,887	251,336	229,456
Other expense (income), net	515	290	(2,897)
Loss on early extinguishment of debt	0	0	6,131
Loss (gain) on sale of businesses	0	3,376	(687)
Interest expense, net of interest income	77,657	73,120	78,670
Income from operations before provision for income taxes	269,715	174,550	148,239
Property, plant and equipment, net	1,863,175	1,525,298
Goodwill	1,227,042	527,023	525,013
Permits and other intangibles, net	644,912	386,620
Permits and other intangibles, net	1,871,954	913,643
Environmental Services
Segment Reporting Information [Line Items]
Total revenues	3,032,454	2,635,901	2,795,994
Reconciliation to Consolidated Statements of Operations:
Goodwill	1,085,534		401,680
Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Total revenues	772,813	507,906	615,060
Reconciliation to Consolidated Statements of Operations:
Goodwill	141,508		123,333
Operating segments | Environmental Services
Segment Reporting Information [Line Items]
Total revenues	3,025,907	2,637,641	2,802,682
Adjusted EBITDA	659,718	665,918	600,413
Reconciliation to Consolidated Statements of Operations:
Property, plant and equipment, net	1,374,913	1,068,910
Goodwill	1,085,534	401,918
Permits and other intangibles, net	498,739	228,237
Permits and other intangibles, net	1,584,273	630,155
Operating segments | Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Total revenues	779,360	506,166	608,372
Adjusted EBITDA	227,354	83,214	128,249
Reconciliation to Consolidated Statements of Operations:
Property, plant and equipment, net	373,721	366,160
Goodwill	141,508	125,105
Permits and other intangibles, net	146,173	158,383
Permits and other intangibles, net	287,681	283,488
Intersegment revenues, net | Environmental Services
Segment Reporting Information [Line Items]
Total revenues	6,547	(1,740)	(6,688)
Intersegment revenues, net | Safety-Kleen Sustainability Solutions
Segment Reporting Information [Line Items]
Total revenues	(6,547)	1,740	6,688
Corporate Items
Segment Reporting Information [Line Items]
Total revenues	299	290	1,136
Adjusted EBITDA	(210,466)	(175,328)	(170,529)
Reconciliation to Consolidated Statements of Operations:
Property, plant and equipment, net	114,541	90,228
Operating segments and corporate non segment
Segment Reporting Information [Line Items]
Total revenues	$ 299	$ 290	$ 1,136