REVENUES (Tables)

9 Months Ended

Sep. 30, 2018

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

The following table presents the Company’s revenues disaggregated by revenue source (in thousands):

	For the Three Months Ended September 30, 2018
	Environmental Services		Safety-Kleen		Corporate			Total
Primary Geographical Markets
United States	$	410,792	$	307,497	$	(66	)	$	718,223
Canada	98,021		26,404		533			124,958
Total third party revenues	$	508,813	$	333,901	$	467		$	843,181
Sources of Revenue (1)
Technical Services	$	264,769	$	—	$	—		$	264,769
Field and Emergency Response Services	77,025		—		—			77,025
Industrial Services	134,323		—		—			134,323
Oil, Gas and Lodging Services and Other	32,696		—		467			33,163
Safety-Kleen Environmental Services	—		200,681		—			200,681
Kleen Performance Products	—		133,220		—			133,220
Total third party revenues	$	508,813	$	333,901	$	467		$	843,181

	For the Three Months Ended September 30, 2017
	Environmental Services		Safety-Kleen		Corporate		Total
Primary Geographical Markets
United States	$	334,625	$	290,653	$	468	$	625,746
Canada	105,538		24,375		187		130,100
Total third party revenues	$	440,163	$	315,028	$	655	$	755,846
Sources of Revenue (1)
Technical Services	$	246,323	$	—	$	—	$	246,323
Field and Emergency Response Services	76,446		—		—		76,446
Industrial Services	90,894		—		—		90,894
Oil, Gas and Lodging Services and Other	26,500		—		655		27,155
Safety-Kleen Environmental Services	—		191,420		—		191,420
Kleen Performance Products	—		123,608		—		123,608
Total third party revenues	$	440,163	$	315,028	$	655	$	755,846

	For the Nine Months Ended September 30, 2018
	Environmental Services		Safety-Kleen		Corporate		Total
Primary Geographical Markets
United States	$	1,162,891	$	901,198	$	442	$	2,064,531
Canada	305,526		71,336		706		377,568
Total third party revenues	$	1,468,417	$	972,534	$	1,148	$	2,442,099
Sources of Revenue (1)
Technical Services	$	758,081	$	—	$	—	$	758,081
Field and Emergency Response Services	223,052		—		—		223,052
Industrial Services	399,132		—		—		399,132
Oil, Gas and Lodging Services and Other	88,152		—		1,148		89,300
Safety-Kleen Environmental Services	—		594,876		—		594,876
Kleen Performance Products	—		377,658		—		377,658
Total third party revenues	$	1,468,417	$	972,534	$	1,148	$	2,442,099

	For the Nine Months Ended September 30, 2017
	Environmental Services		Safety-Kleen		Corporate		Total
Primary Geographical Markets
United States	$	991,731	$	843,341	$	756	$	1,835,828
Canada	293,970		67,544		233		361,747
Total third party revenues	$	1,285,701	$	910,885	$	989	$	2,197,575
Sources of Revenue (1)
Technical Services	$	731,028	$	—	$	—	$	731,028
Field and Emergency Response Services	208,172		—		—		208,172
Industrial Services	265,695		—		—		265,695
Oil, Gas and Lodging Services and Other	80,806		—		989		81,795
Safety-Kleen Environmental Services	—		575,964		—		575,964
Kleen Performance Products	—		334,921		—		334,921
Total third party revenues	$	1,285,701	$	910,885	$	989	$	2,197,575

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1. All revenue except Kleen Performance Products and product sales within Safety-Kleen Environmental Services, which includes allied products and direct blended oil sales, are recognized over time. Kleen Performance Products and Safety-Kleen Environmental Services product sales are recognized at a point in time.

Contract Balances

Contract Balances

	September 30, 2018		December 31, 2017		September 30, 2017		December 31, 2016
Receivables	$	608,645	$	528,924	$	531,696	$	496,226
Contract Assets (Unbilled Receivables)	63,964		35,922		40,933		36,190
Contract Liabilities (Deferred Revenue)	65,172		67,822		69,236		64,397