GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)

9 Months Ended

Sep. 30, 2023

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes to Goodwill

The changes in goodwill by segment for the nine months ended September 30, 2023 were as follows (in thousands):

	Environmental Services		Safety-Kleen Sustainability Solutions		Totals
Balance at January 1, 2023	$	1,071,846	$	175,032	$	1,246,878
Increase from current period acquisition	39,088		—		39,088
Measurement period adjustments from prior period acquisitions	—		342		342
Foreign currency translation	118		47		165
Balance at September 30, 2023	$	1,111,052	$	175,421	$	1,286,473

Schedule of Finite-Lived Intangible Assets

As of September 30, 2023 and December 31, 2022, the Company's intangible assets consisted of the following (in thousands):

	September 30, 2023						December 31, 2022
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	189,982	$	115,122	$	74,860	$	188,373	$	109,036	$	79,337
Customer and supplier relationships	604,493		251,378		353,115		583,709		229,368		354,341
Other intangible assets	100,012		34,547		65,465		89,388		24,818		64,570
Total amortizable permits and other intangible assets	894,487		401,047		493,440		861,470		363,222		498,248
Trademarks and trade names	120,100		—		120,100		122,534		—		122,534
Total permits and other intangible assets	$	1,014,587	$	401,047	$	613,540	$	984,004	$	363,222	$	620,782

Summary of Indefinite-Lived Intangible Assets

As of September 30, 2023 and December 31, 2022, the Company's intangible assets consisted of the following (in thousands):

	September 30, 2023						December 31, 2022
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	189,982	$	115,122	$	74,860	$	188,373	$	109,036	$	79,337
Customer and supplier relationships	604,493		251,378		353,115		583,709		229,368		354,341
Other intangible assets	100,012		34,547		65,465		89,388		24,818		64,570
Total amortizable permits and other intangible assets	894,487		401,047		493,440		861,470		363,222		498,248
Trademarks and trade names	120,100		—		120,100		122,534		—		122,534
Total permits and other intangible assets	$	1,014,587	$	401,047	$	613,540	$	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 September 30, 2023 was as follows (in thousands):

Years Ending December 31,	Expected Amortization
2023 (three months)	$	12,420
2024	46,437
2025	43,042
2026	41,143
2027	39,067
Thereafter	311,331
	$	493,440