REVENUES (Tables)

3 Months Ended

Mar. 31, 2023

Revenue from Contract with Customer [Abstract]

Schedule of Disaggregation of Revenue

The following tables present the Company's third-party revenue disaggregated by source of revenue and geography (in thousands):

	For the Three Months Ended March 31, 2023
	Environmental Services		Safety-Kleen Sustainability Solutions		Corporate		Total
Primary Geographical Markets
United States	$	958,584	$	221,771	$	107	$	1,180,462
Canada	102,398		24,527		—		126,925
Total third-party revenues	$	1,060,982	$	246,298	$	107	$	1,307,387
Sources of Revenue
Technical Services	$	366,509	$	—	$	—	$	366,509
Industrial Services and Other	336,379		—		107		336,486
Field and Emergency Response Services	148,086		—		—		148,086
Safety-Kleen Environmental Services	210,008		49,559		—		259,567
Safety-Kleen Oil	—		196,739		—		196,739
Total third-party revenues	$	1,060,982	$	246,298	$	107	$	1,307,387

	For the Three Months Ended March 31, 2022
	Environmental Services		Safety-Kleen Sustainability Solutions		Corporate		Total
Primary Geographical Markets
United States	$	834,678	$	202,530	$	72	$	1,037,280
Canada	106,120		25,709		—		131,829
Total third-party revenues	$	940,798	$	228,239	$	72	$	1,169,109
Sources of Revenue
Technical Services	$	323,656	$	—	$	—	$	323,656
Industrial Services and Other	308,838		—		72		308,910
Field and Emergency Response Services	132,359		—		—		132,359
Safety-Kleen Environmental Services	175,945		44,388		—		220,333
Safety-Kleen Oil	—		183,851		—		183,851
Total third-party revenues	$	940,798	$	228,239	$	72	$	1,169,109

Schedule of Contract Balances

(in thousands)	March 31, 2023		December 31, 2022
Receivables	$	963,659	$	964,603
Contract assets (unbilled receivables)	137,507		107,010
Contract liabilities (deferred revenue)	101,336		94,094