REVENUES (Tables)

12 Months Ended

Dec. 31, 2018

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

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

	For the Year Ended December 31, 2018
	Environmental Services		Safety-Kleen		Corporate		Total
Primary Geographical Markets
United States	$	1,598,402	$	1,196,661	$	1,082	$	2,796,145
Canada	405,441		98,694		23		504,158
Total third party revenues	$	2,003,843	$	1,295,355	$	1,105	$	3,300,303
Sources of Revenue (1)
Technical Services	$	1,037,388	$	—	$	—	$	1,037,388
Field and Emergency Response Services	304,727		—		—		304,727
Industrial Services	541,895		—		—		541,895
Oil, Gas and Lodging Services and Other	119,833		—		1,105		120,938
Safety-Kleen Environmental Services	—		795,077		—		795,077
Kleen Performance Products	—		500,278		—		500,278
Total third party revenues	$	2,003,843	$	1,295,355	$	1,105	$	3,300,303

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1. All revenue except oil and oil product sales within Kleen Performance Products and product sales within Safety-Kleen Environmental Services, which include various automotive related fluids, shop supplies 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

	December 31, 2018		December 31, 2017
Receivables	$	606,952	$	528,924
Contract Assets (Unbilled Receivables)	54,794		35,922
Contract Liabilities (Deferred Revenue)	61,843		67,822