GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)

12 Months Ended

Dec. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes to Goodwill

The changes in goodwill for the years ended December 31, 2020 and 2019 were as follows (in thousands):

	Environmental Services		Safety-Kleen		Totals
Balance at January 1, 2019	$	207,019	$	307,170	$	514,189
Increase from current period acquisitions	7,378		5,225		12,603
Measurement period adjustments from prior period acquisitions	(2,675)		(1,355)		(4,030)
Foreign currency translation	809		1,442		2,251
Balance at December 31, 2019	$	212,531	$	312,482	$	525,013
Increase from current period acquisition	—		1,439		1,439
Measurement period adjustments from prior period acquisitions	23		—		23
Decrease from disposition of businesses	(674)		—		(674)
Foreign currency translation	506		716		1,222
Balance at December 31, 2020	$	212,386	$	314,637	$	527,023

Schedule of Finite-Lived Intangible Assets by Major Class

As of December 31, 2020 and 2019, the Company's finite-lived and indefinite-lived intangible assets consisted of the following (in thousands):

	December 31, 2020						December 31, 2019
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	183,766	$	95,033	$	88,733	$	184,235	$	87,228	$	97,007
Customer and supplier relationships	382,083		211,895		170,188		401,696		207,884		193,812
Other intangible assets	39,287		34,744		4,543		38,331		33,018		5,313
Total amortizable permits and other intangible assets	605,136		341,672		263,464		624,262		328,130		296,132
Trademarks and trade names	123,156		—		123,156		122,934		—		122,934
Total permits and other intangible assets	$	728,292	$	341,672	$	386,620	$	747,196	$	328,130	$	419,066

Schedule of Indefinite-Lived Intangible Assets

As of December 31, 2020 and 2019, the Company's finite-lived and indefinite-lived intangible assets consisted of the following (in thousands):

	December 31, 2020						December 31, 2019
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	183,766	$	95,033	$	88,733	$	184,235	$	87,228	$	97,007
Customer and supplier relationships	382,083		211,895		170,188		401,696		207,884		193,812
Other intangible assets	39,287		34,744		4,543		38,331		33,018		5,313
Total amortizable permits and other intangible assets	605,136		341,672		263,464		624,262		328,130		296,132
Trademarks and trade names	123,156		—		123,156		122,934		—		122,934
Total permits and other intangible assets	$	728,292	$	341,672	$	386,620	$	747,196	$	328,130	$	419,066

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, 2020 is as follows (in thousands):

Years ending December 31,	Expected Amortization
2021	$	30,163
2022	29,911
2023	25,587
2024	24,092
2025	23,121
Thereafter	130,590
	$	263,464