REVENUES (Tables)

9 Months Ended

Sep. 30, 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 September 30, 2023
	Environmental Services		Safety-Kleen Sustainability Solutions		Corporate		Total
Primary Geographical Markets
United States	$	1,017,224	$	206,860	$	112	$	1,224,196
Canada	118,055		23,445		—		141,500
Total third-party revenues	$	1,135,279	$	230,305	$	112	$	1,365,696
Sources of Revenue
Technical Services	$	403,889	$	—	$	—	$	403,889
Industrial Services and Other	350,251		—		112		350,363
Field and Emergency Response Services	155,046		—		—		155,046
Safety-Kleen Environmental Services	226,093		59,458		—		285,551
Safety-Kleen Oil	—		170,847		—		170,847
Total third-party revenues	$	1,135,279	$	230,305	$	112	$	1,365,696

	For the Three Months Ended September 30, 2022
	Environmental Services		Safety-Kleen Sustainability Solutions		Corporate		Total
Primary Geographical Markets
United States	$	960,737	$	249,035	$	283	$	1,210,055
Canada	119,295		33,736		—		153,031
Total third-party revenues	$	1,080,032	$	282,771	$	283	$	1,363,086
Sources of Revenue
Technical Services	$	398,664	$	—	$	—	$	398,664
Industrial Services and Other	332,025		—		283		332,308
Field and Emergency Response Services	150,031		—		—		150,031
Safety-Kleen Environmental Services	199,312		52,072		—		251,384
Safety-Kleen Oil	—		230,699		—		230,699
Total third-party revenues	$	1,080,032	$	282,771	$	283	$	1,363,086

	For the Nine Months Ended September 30, 2023
	Environmental Services		Safety-Kleen Sustainability Solutions		Corporate		Total
Primary Geographical Markets
United States	$	3,017,547	$	641,625	$	335	$	3,659,507
Canada	340,196		71,280		—		411,476
Total third-party revenues	$	3,357,743	$	712,905	$	335	$	4,070,983
Sources of Revenue
Technical Services	$	1,160,306	$	—	$	—	$	1,160,306
Industrial Services and Other	1,086,175		—		335		1,086,510
Field and Emergency Response Services	457,491		—		—		457,491
Safety-Kleen Environmental Services	653,771		171,469		—		825,240
Safety-Kleen Oil	—		541,436		—		541,436
Total third-party revenues	$	3,357,743	$	712,905	$	335	$	4,070,983

	For the Nine Months Ended September 30, 2022
	Environmental Services		Safety-Kleen Sustainability Solutions		Corporate		Total
Primary Geographical Markets
United States	$	2,740,994	$	688,444	$	434	$	3,429,872
Canada	364,342		94,293		—		458,635
Total third-party revenues	$	3,105,336	$	782,737	$	434	$	3,888,507
Sources of Revenue
Technical Services	$	1,109,339	$	—	$	—	$	1,109,339
Industrial Services and Other	1,001,733		—		434		1,002,167
Field and Emergency Response Services	427,250		—		—		427,250
Safety-Kleen Environmental Services	567,014		145,841		—		712,855
Safety-Kleen Oil	—		636,896		—		636,896
Total third-party revenues	$	3,105,336	$	782,737	$	434	$	3,888,507

Schedule of Contract Balances

(in thousands)	September 30, 2023		December 31, 2022
Receivables	$	1,010,335	$	964,603
Contract assets (unbilled receivables)	130,888		107,010
Contract liabilities (deferred revenue)	102,468		94,094