Asset Impairments, Other Charges, and Inventory Valuation Provision - Summary of Charges (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Dec. 31, 2017	Dec. 31, 2017
Restructuring and Related Activities [Abstract]
Workforce reduction and related charges		$ 3,057
CEC asset impairments		32,274
Station closures and related charges		25,557
LCFS Credits charge	$ 7,000	7,046
Total asset impairments and other charges		67,934
Inventory valuation provision		13,158
Total charges		$ 81,092

Restructuring Costs, Asset Impairment Charges, And Inventory Write-Down

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Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Includes, but is not limited to, one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, and relocating employees, and termination benefits associated with an ongoing benefit arrangement. Excludes expenses associated with special or contractual termination benefits, a discontinued operation or an asset retirement obligation.

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Amount of loss from reductions in inventory due to subsequent measurement adjustments, including, but not limited to, physical deterioration, obsolescence, or changes in price levels.

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Amount of increase (decrease) in liabilities subject to compromise.

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Amount, after cash payment, of expenses associated with exit or disposal activities pursuant to an authorized plan and expenses resulting from the write-down of assets. Excludes expenses related to a business combination, a discontinued operation or an asset retirement obligation.

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Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

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