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Fair Value Measurements (Details) (USD $)
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12 Months Ended | ||
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Dec. 31, 2011
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Dec. 31, 2010
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Dec. 31, 2009
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| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||
| Assets | $ 1,601,000 | ||
| Liabilities | 4,720,000 | ||
| Asset retirement obligations incurred | 1,390,000 | 1,328,000 | 361,000 |
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Level 1 [Member] | Fixed Price Swaps [Member]
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| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||
| Assets | |||
| Liabilities | |||
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Level 2 [Member] | Fixed Price Swaps [Member]
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|||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||
| Assets | 1,601,000 | ||
| Liabilities | 4,720,000 | ||
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Level 3 [Member] | Fixed Price Swaps [Member]
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| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||
| Assets | |||
| Liabilities | |||
| X | ||||||||||
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- Definition
Amount of asset retirement obligations incurred during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Fair values as of the balance sheet date for all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments and which are expected to be converted into cash or otherwise disposed of within a year or the normal operating cycle, if longer, net of the effects of master netting arrangements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Fair values as of the balance sheet date of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, and which are expected to be extinguished or otherwise disposed of within a year or the normal operating cycle, if longer, net of the effects of master netting arrangements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Details
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