GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)

6 Months Ended

Jun. 30, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes to Goodwill

The changes in goodwill by segment for the six months ended June 30, 2021 were as follows (in thousands):

	Environmental Services		Safety-Kleen Sustainability Solutions		Totals
Balance at January 1, 2021	$	401,918	$	125,105	$	527,023
Increase from current period acquisition	—		15,958		15,958
Foreign currency translation	1,218		440		1,658
Balance at June 30, 2021	$	403,136	$	141,503	$	544,639

Schedule of Finite-Lived Intangible Assets

As of June 30, 2021 and December 31, 2020, the Company's intangible assets consisted of the following (in thousands):

	June 30, 2021						December 31, 2020
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	186,292	$	99,143	$	87,149	$	183,766	$	95,033	$	88,733
Customer and supplier relationships	366,913		207,196		159,717		382,083		211,895		170,188
Other intangible assets	21,223		17,309		3,914		39,287		34,744		4,543
Total amortizable permits and other intangible assets	574,428		323,648		250,780		605,136		341,672		263,464
Trademarks and trade names	123,450		—		123,450		123,156		—		123,156
Total permits and other intangible assets	$	697,878	$	323,648	$	374,230	$	728,292	$	341,672	$	386,620

Summary of Indefinite-Lived Intangible Assets

As of June 30, 2021 and December 31, 2020, the Company's intangible assets consisted of the following (in thousands):

	June 30, 2021						December 31, 2020
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	186,292	$	99,143	$	87,149	$	183,766	$	95,033	$	88,733
Customer and supplier relationships	366,913		207,196		159,717		382,083		211,895		170,188
Other intangible assets	21,223		17,309		3,914		39,287		34,744		4,543
Total amortizable permits and other intangible assets	574,428		323,648		250,780		605,136		341,672		263,464
Trademarks and trade names	123,450		—		123,450		123,156		—		123,156
Total permits and other intangible assets	$	697,878	$	323,648	$	374,230	$	728,292	$	341,672	$	386,620

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 June 30, 2021 was as follows (in thousands):

Years Ending December 31,	Expected Amortization
2021 (six months)	$	15,119
2022	30,075
2023	25,735
2024	24,231
2025	23,254
Thereafter	132,366
	$	250,780