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Derivative Financial Instruments (Narrative) (Details) (USD $)
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3 Months Ended | ||||||
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Mar. 31, 2012
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Mar. 31, 2011
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Mar. 31, 2012
Accrued Liabilities [Member]
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Dec. 31, 2011
Accrued Liabilities [Member]
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Dec. 31, 2011
Prepaid And Other Assets [Member]
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Dec. 31, 2011
Other Assets [Member]
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Mar. 31, 2012
Other Long-Term Liabilities [Member]
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| Derivatives, Fair Value [Line Items] | |||||||
| Fair value of commodity derivative contracts | $ 23,200,000 | $ 7,200,000 | $ 2,300,000 | $ 1,800,000 | $ 13,700,000 | ||
| Realized gain (loss) on commodity derivatives | 5,800,000 | 2,200,000 | |||||
| Unrealized gain (loss) on commodity derivatives | $ 33,800,000 | $ 21,600,000 | |||||
| X | ||||||||||
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- Definition
Fair value of derivative liability, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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- Definition
The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of open agreements to purchase or sell mineral resources, energy, and agricultural products at some future point held at each balance sheet date, that was included in earnings for the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The realized gain or loss related to commodity contracts that have closed. No definition available.
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