GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)

3 Months Ended

Mar. 31, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes to Goodwill

The changes in goodwill by segment for the three months ended March 31, 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	—		15,875		15,875
Foreign currency translation	520		187		707
Balance at March 31, 2021	$	402,438	$	141,167	$	543,605

Schedule of Finite-Lived Intangible Assets

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

	March 31, 2021						December 31, 2020
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	184,675	$	97,061	$	87,614	$	183,766	$	95,033	$	88,733
Customer and supplier relationships	372,860		207,929		164,931		382,083		211,895		170,188
Other intangible assets	39,334		35,107		4,227		39,287		34,744		4,543
Total amortizable permits and other intangible assets	596,869		340,097		256,772		605,136		341,672		263,464
Trademarks and trade names	123,281		—		123,281		123,156		—		123,156
Total permits and other intangible assets	$	720,150	$	340,097	$	380,053	$	728,292	$	341,672	$	386,620

Summary of Indefinite-Lived Intangible Assets

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

	March 31, 2021						December 31, 2020
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	184,675	$	97,061	$	87,614	$	183,766	$	95,033	$	88,733
Customer and supplier relationships	372,860		207,929		164,931		382,083		211,895		170,188
Other intangible assets	39,334		35,107		4,227		39,287		34,744		4,543
Total amortizable permits and other intangible assets	596,869		340,097		256,772		605,136		341,672		263,464
Trademarks and trade names	123,281		—		123,281		123,156		—		123,156
Total permits and other intangible assets	$	720,150	$	340,097	$	380,053	$	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 March 31, 2021 was as follows (in thousands):

Years Ending December 31,	Expected Amortization
2021 (nine months)	$	22,674
2022	30,013
2023	25,681
2024	24,183
2025	23,205
Thereafter	131,016
	$	256,772