Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2016	Dec. 31, 2015
Restricted Cash
Current restricted cash	$ 28,557	$ 28,533
Long-term restricted cash	7,313	7,325
Inventories
Materials and supplies inventory	67,100	84,400
Hydrocarbons inventory	100	800
Write down of materials and supplies	15,700
Restricted Cash \| Petroleum agreements - performance guarantees
Restricted Cash
Current restricted cash	4,200	4,100
Long-term restricted cash	$ 7,300	7,300
Restricted Cash \| Facility interest or the Senior Notes plus the Corporate Revolver interest
Restricted Cash
Restricted cash period required as per commercial debt facility to meet interest and commitment fee payments	6 months
Current restricted cash	$ 24,400	$ 24,400
Senior Notes \| 7.875% senior notes due 2021
Restricted Cash
Interest rate	7.875%

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+ References

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Contractual interest rate for funds borrowed, under the debt agreement.

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Carrying amount as of the balance sheet date of petroleum or crude oil.

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Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of products used directly or indirectly in the manufacturing or production process, which may or may not become part of the final product. May also include items used in the storage, presentation or transportation of physical goods.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.6(a)(5))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 330
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 5.BB)
-URI http://asc.fasb.org/extlink&oid=27011343&loc=d3e100047-122729

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The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. For a classified balance sheet represents the current portion only (the noncurrent portion has a separate concept); there is a separate and distinct element for unclassified presentations.

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Cash and equivalents whose use in whole or in part is restricted for the long-term, generally by contractual agreements or regulatory requirements.

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