GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)

12 Months Ended

Dec. 31, 2023

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes to Goodwill

The changes in goodwill for the years ended December 31, 2023 and 2022 were as follows (in thousands):

	Environmental Services		Safety-Kleen Sustainability Solutions		Total
Balance at January 1, 2022	$	1,085,534	$	141,508	$	1,227,042
Increase from current period acquisitions	—		34,510		34,510
Measurement period adjustments from prior period acquisition	(6,762)		—		(6,762)
Decrease from disposition of business	(4,412)		—		(4,412)
Foreign currency translation	(2,514)		(986)		(3,500)
Balance at December 31, 2022	$	1,071,846	$	175,032	$	1,246,878
Increase from current period acquisition	39,346		—		39,346
Measurement period adjustments from prior period acquisitions	—		360		360
Foreign currency translation	821		331		1,152
Balance at December 31, 2023	$	1,112,013	$	175,723	$	1,287,736

Schedule of Finite-Lived Intangible Assets by Major Class

As of December 31, 2023 and 2022, the Company's intangible assets consisted of the following (in thousands):

	December 31, 2023						December 31, 2022
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	191,747	$	117,556	$	74,191	$	188,373	$	109,036	$	79,337
Customer and supplier relationships	604,994		258,879		346,115		583,709		229,368		354,341
Other intangible assets	100,068		37,862		62,206		89,388		24,818		64,570
Total amortizable permits and other intangible assets	896,809		414,297		482,512		861,470		363,222		498,248
Trademarks and trade names	120,285		—		120,285		122,534		—		122,534
Total permits and other intangible assets	$	1,017,094	$	414,297	$	602,797	$	984,004	$	363,222	$	620,782

Schedule of Indefinite-Lived Intangible Assets

As of December 31, 2023 and 2022, the Company's intangible assets consisted of the following (in thousands):

	December 31, 2023						December 31, 2022
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	191,747	$	117,556	$	74,191	$	188,373	$	109,036	$	79,337
Customer and supplier relationships	604,994		258,879		346,115		583,709		229,368		354,341
Other intangible assets	100,068		37,862		62,206		89,388		24,818		64,570
Total amortizable permits and other intangible assets	896,809		414,297		482,512		861,470		363,222		498,248
Trademarks and trade names	120,285		—		120,285		122,534		—		122,534
Total permits and other intangible assets	$	1,017,094	$	414,297	$	602,797	$	984,004	$	363,222	$	620,782

Schedule of Expected Amortization for the Net Carrying Amount of Finite Lived Intangible Assets

The expected amortization of the net carrying amount of finite-lived intangible assets at December 31, 2023 was as follows (in thousands):

Years ending December 31,	Expected Amortization
2024	$	46,639
2025	43,231
2026	41,385
2027	39,245
2028	37,975
Thereafter	274,037
	$	482,512