REVENUES

12 Months Ended

Dec. 31, 2019

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue

We disaggregate the Company’s third party revenues by geographic location and source of revenue as we believe these categories depict how revenue and cash flows are affected by economic factors (in thousands):



	For the year ended December 31, 2019
	Environmental Services		Safety-Kleen		Corporate			Total
Primary Geographical Markets
United States	$	1,721,322	$	1,220,096	$	(586	)	$	2,940,832
Canada	371,041		98,595		1,722			471,358
Total third party revenues	$	2,092,363	$	1,318,691	$	1,136		$	3,412,190

Sources of Revenue ⁽¹⁾
Technical Services	$	1,120,043	$	—	$	—		$	1,120,043
Field and Emergency Response Services	340,906		—		—			340,906
Industrial Services	514,390		—		—			514,390
Oil, Gas and Lodging Services and Other	117,024		—		1,136			118,160
Safety-Kleen Environmental Services	—		851,520		—			851,520
Safety-Kleen Oil ⁽²⁾	—		467,171		—			467,171
Total third party revenues	$	2,092,363	$	1,318,691	$	1,136		$	3,412,190



	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
Safety-Kleen Oil ⁽²⁾	—		500,278		—		500,278
Total third party revenues	$	2,003,843	$	1,295,355	$	1,105	$	3,300,303

_____________________


(1)	All revenue except oil and oil product sales within Safety-Kleen Oil 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. Safety-Kleen Oil and Safety-Kleen Environmental Services product sales are recognized at a point in time.


(2)	Safety-Kleen Oil was formerly known as Kleen Performance Products.

Contract Balances



(in thousands)	December 31, 2019		December 31, 2018
Receivables	$	644,738	$	606,952
Contract assets (unbilled receivables)	56,326		54,794
Contract liabilities (deferred revenue)	73,370		61,843

The timing of revenue recognition, billings and cash collections results in billed accounts receivable, unbilled receivables (contract assets) and customer advances and deposits or deferred revenue (contract liabilities) on the consolidated balance sheet. Generally, billing occurs subsequent to revenue recognition, as a right to payment is not just subject to passage of time, resulting in contract assets. Contract assets are generally classified as current. The Company sometimes receives advances or deposits from its customers before revenue is recognized, resulting in contract liabilities. These assets and liabilities are reported on the consolidated balance sheet on a contract-by-contract basis at the end of each reporting period. The contract liability balances at the beginning of each period presented were generally fully recognized in the subsequent three-month period.

Variable Consideration

The nature of the Company's contracts give rise to certain types of variable consideration, including in limited cases volume discounts. Accordingly, management establishes a revenue allowance to cover the estimated amounts of revenue that may need to be credited to customers' accounts in future periods. The Company estimates the amount of variable consideration to include in the estimated transaction price based on historical experience, anticipated performance and its best judgment at the time and to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved.

Contract Costs

Contract costs include direct and incremental costs to obtain or fulfill a contract. The Company’s contract costs that are subject to capitalization are comprised of costs associated with parts washer services and costs associated with the treatment and disposal of waste. Parts washer costs include costs of solvent, commissions paid relating to revenue generated from parts washer services, and transportation costs associated with transferring the product picked up from the services as it is returned to the Company’s facilities or a third party site. Costs related to the treatment of waste include costs for waste receiving, drum movement and storage, waste consolidation and transportation between facilities. Deferred costs associated with parts washer

services are amortized ratably over the average service interval, which ranges between four and 16 weeks. Deferred costs related to treatment and disposal of waste are recognized when the corresponding waste is disposed of and are included in deferred costs within total current assets in the Company’s consolidated balance sheets. The deferred contract cost balances at the beginning of each period presented were fully recognized in cost of revenue in the subsequent three-month period.