REVENUES (Tables)

6 Months Ended

Jun. 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 June 30, 2023
	Environmental Services		Safety-Kleen Sustainability Solutions		Corporate		Total
Primary Geographical Markets
United States	$	1,041,739	$	212,994	$	116	$	1,254,849
Canada	119,743		23,308		—		143,051
Total third-party revenues	$	1,161,482	$	236,302	$	116	$	1,397,900
Sources of Revenue
Technical Services	$	389,908	$	—	$	—	$	389,908
Industrial Services and Other	399,545		—		116		399,661
Field and Emergency Response Services	154,359		—		—		154,359
Safety-Kleen Environmental Services	217,670		62,452		—		280,122
Safety-Kleen Oil	—		173,850		—		173,850
Total third-party revenues	$	1,161,482	$	236,302	$	116	$	1,397,900

	For the Three Months Ended June 30, 2022
	Environmental Services		Safety-Kleen Sustainability Solutions		Corporate		Total
Primary Geographical Markets
United States	$	945,579	$	236,879	$	79	$	1,182,537
Canada	138,927		34,848		—		173,775
Total third-party revenues	$	1,084,506	$	271,727	$	79	$	1,356,312
Sources of Revenue
Technical Services	$	387,019	$	—	$	—	$	387,019
Industrial Services and Other	360,870		—		79		360,949
Field and Emergency Response Services	144,860		—		—		144,860
Safety-Kleen Environmental Services	191,757		49,381		—		241,138
Safety-Kleen Oil	—		222,346		—		222,346
Total third-party revenues	$	1,084,506	$	271,727	$	79	$	1,356,312

	For the Six Months Ended June 30, 2023
	Environmental Services		Safety-Kleen Sustainability Solutions		Corporate		Total
Primary Geographical Markets
United States	$	2,000,323	$	434,765	$	223	$	2,435,311
Canada	222,141		47,835		—		269,976
Total third-party revenues	$	2,222,464	$	482,600	$	223	$	2,705,287
Sources of Revenue
Technical Services	$	756,417	$	—	$	—	$	756,417
Industrial Services and Other	735,924		—		223		736,147
Field and Emergency Response Services	302,445		—		—		302,445
Safety-Kleen Environmental Services	427,678		112,011		—		539,689
Safety-Kleen Oil	—		370,589		—		370,589
Total third-party revenues	$	2,222,464	$	482,600	$	223	$	2,705,287

	For the Six Months Ended June 30, 2022
	Environmental Services		Safety-Kleen Sustainability Solutions		Corporate		Total
Primary Geographical Markets
United States	$	1,780,257	$	439,409	$	151	$	2,219,817
Canada	245,047		60,557		—		305,604
Total third-party revenues	$	2,025,304	$	499,966	$	151	$	2,525,421
Sources of Revenue
Technical Services	$	710,675	$	—	$	—	$	710,675
Industrial Services and Other	669,708		—		151		669,859
Field and Emergency Response Services	277,219		—		—		277,219
Safety-Kleen Environmental Services	367,702		93,769		—		461,471
Safety-Kleen Oil	—		406,197		—		406,197
Total third-party revenues	$	2,025,304	$	499,966	$	151	$	2,525,421

Schedule of Contract Balances

(in thousands)	June 30, 2023		December 31, 2022
Receivables	$	981,233	$	964,603
Contract assets (unbilled receivables)	122,679		107,010
Contract liabilities (deferred revenue)	105,327		94,094