GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)

12 Months Ended

Dec. 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes to Goodwill

The changes in goodwill for the years ended December 31, 2018 and 2017 were as follows (in thousands):

	Environmental Services			Safety-Kleen			Totals
Balance at January 1, 2017	$	169,084		$	296,070		$	465,154
Increase from current period acquisitions	3,000			5,687			8,687
Measurement period adjustments from prior period acquisitions	—			2,186			2,186
Decrease from disposition of business	(1,300		)	—			(1,300		)
Foreign currency translation	1,602			2,194			3,796
Balance at December 31, 2017	$	172,386		$	306,137		$	478,523
Increase from current period acquisitions	37,007			3,697			40,704
Measurement period adjustments from prior period acquisitions	(78		)	—			(78		)
Foreign currency translation	(2,296		)	(2,664		)	(4,960		)
Balance at December 31, 2018	$	207,019		$	307,170		$	514,189

Schedule of Finite-Lived Intangible Assets by Major Class

As of December 31, 2018 and 2017, the Company's finite-lived and indefinite-lived intangible assets consisted of the following (in thousands):

	December 31, 2018						December 31, 2017
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	177,583	$	79,358	$	98,225	$	174,721	$	74,347	$	100,374
Customer and supplier relationships	393,487		179,824		213,663		399,224		158,972		240,252
Other intangible assets	37,262		29,743		7,519		36,766		31,592		5,174
Total amortizable permits and other intangible assets	608,332		288,925		319,407		610,711		264,911		345,800
Trademarks and trade names	122,468		—		122,468		123,328		—		123,328
Total permits and other intangible assets	$	730,800	$	288,925	$	441,875	$	734,039	$	264,911	$	469,128

Schedule of Indefinite-Lived Intangible Assets

As of December 31, 2018 and 2017, the Company's finite-lived and indefinite-lived intangible assets consisted of the following (in thousands):

	December 31, 2018						December 31, 2017
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	177,583	$	79,358	$	98,225	$	174,721	$	74,347	$	100,374
Customer and supplier relationships	393,487		179,824		213,663		399,224		158,972		240,252
Other intangible assets	37,262		29,743		7,519		36,766		31,592		5,174
Total amortizable permits and other intangible assets	608,332		288,925		319,407		610,711		264,911		345,800
Trademarks and trade names	122,468		—		122,468		123,328		—		123,328
Total permits and other intangible assets	$	730,800	$	288,925	$	441,875	$	734,039	$	264,911	$	469,128

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, 2018 is as follows (in thousands):

Years Ending December 31,	Expected Amortization
2019	$	33,091
2020	30,195
2021	27,553
2022	27,386
2023	23,468
Thereafter	177,714
	$	319,407