GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes to Goodwill

The changes in goodwill for the years ended December 31, 2017 and 2016 were as follows (in thousands):

	Technical Services			Industrial and Field Services			Safety-Kleen		Oil, Gas and Lodging Services			Totals
Balance at January 1, 2016	$	49,267		$	105,286		$	266,344	$	32,208		$	453,105
Increase from current period acquisitions	12,572			6,953			26,266		—			45,791
Measurement period adjustments from prior period acquisitions	—			—			2,095		—			2,095
Decrease from disposition of business	—			(4,994		)	—		—			(4,994		)
Goodwill impairment charge	—			—			—		(34,013		)	(34,013		)
Foreign currency translation	(723		)	723			1,365		1,805			3,170
Balance at December 31, 2016	$	61,116		$	107,968		$	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	317			1,285			2,194		—			3,796
Balance at December 31, 2017	$	60,133		$	112,253		$	306,137	$	—		$	478,523

Schedule of Finite-Lived Intangible Assets by Major Class

As of December 31, 2017 and 2016, the Company's finite-lived and indefinite lived intangible assets consisted of the following (in thousands):

	December 31, 2017						December 31, 2016
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	174,721	$	74,347	$	100,374	$	171,637	$	67,301	$	104,336
Customer and supplier relationships	399,224		158,972		240,252		393,426		127,462		265,964
Other intangible assets	36,766		31,592		5,174		34,254		28,456		5,798
Total amortizable permits and other intangible assets	610,711		264,911		345,800		599,317		223,219		376,098
Trademarks and trade names	123,328		—		123,328		122,623		—		122,623
Total permits and other intangible assets	$	734,039	$	264,911	$	469,128	$	721,940	$	223,219	$	498,721

Schedule of Indefinite-Lived Intangible Assets

As of December 31, 2017 and 2016, the Company's finite-lived and indefinite lived intangible assets consisted of the following (in thousands):

	December 31, 2017						December 31, 2016
	Cost		Accumulated Amortization		Net		Cost		Accumulated Amortization		Net
Permits	$	174,721	$	74,347	$	100,374	$	171,637	$	67,301	$	104,336
Customer and supplier relationships	399,224		158,972		240,252		393,426		127,462		265,964
Other intangible assets	36,766		31,592		5,174		34,254		28,456		5,798
Total amortizable permits and other intangible assets	610,711		264,911		345,800		599,317		223,219		376,098
Trademarks and trade names	123,328		—		123,328		122,623		—		122,623
Total permits and other intangible assets	$	734,039	$	264,911	$	469,128	$	721,940	$	223,219	$	498,721

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, 2017 is as follows (in thousands):

Years Ending December 31,	Expected Amortization
2018	$	34,631
2019	31,684
2020	29,130
2021	26,888
2022	26,727
Thereafter	196,740
	$	345,800