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Contingencies (Details) (USD $)
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0 Months Ended | 12 Months Ended | 0 Months Ended | 12 Months Ended | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Feb. 15, 2011
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Apr. 20, 2009
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Dec. 31, 2011
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Dec. 07, 2010
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Feb. 15, 2011
Disgorgement [Member]
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Dec. 31, 2011
Shell Trading Company [Member]
Oil [Member]
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Dec. 31, 2010
Shell Trading Company [Member]
Oil [Member]
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Dec. 31, 2009
Shell Trading Company [Member]
Oil [Member]
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Dec. 31, 2011
Windsor [Member]
Oil [Member]
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Dec. 31, 2010
Windsor [Member]
Oil [Member]
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Dec. 31, 2009
Windsor [Member]
Oil [Member]
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Dec. 31, 2011
Windsor [Member]
Natural Gas Liquids [Member]
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Dec. 31, 2009
Windsor [Member]
Natural Gas Liquids [Member]
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Dec. 31, 2011
Windsor [Member]
Natural Gas [Member]
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Dec. 31, 2010
Windsor [Member]
Natural Gas [Member]
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Dec. 31, 2009
Windsor [Member]
Natural Gas [Member]
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Dec. 31, 2011
Chevron [Member]
Natural Gas [Member]
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Dec. 31, 2010
Chevron [Member]
Natural Gas [Member]
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Dec. 31, 2009
Chevron [Member]
Natural Gas [Member]
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Dec. 31, 2011
Hilcorp Energy Company [Member]
Natural Gas [Member]
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Dec. 31, 2010
Hilcorp Energy Company [Member]
Natural Gas [Member]
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Dec. 31, 2009
Hilcorp Energy Company [Member]
Natural Gas [Member]
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| Contingencies [Line Items] | ||||||||||||||||||||||
| Alleged severance tax | $ 1,800,000 | |||||||||||||||||||||
| Lawsuits filed value | 26,500,000 | 2,275,729 | 6,000,000 | |||||||||||||||||||
| Original number of acreage in litigation | 240 | |||||||||||||||||||||
| Amended number of acreage in litigation | 1,700 | |||||||||||||||||||||
| FDIC insured amount | 250,000 | |||||||||||||||||||||
| Uninsured cash amount | $ 93,397,000 | |||||||||||||||||||||
| Percentage of production sold | 93.00% | 75.00% | 92.00% | 7.00% | 19.00% | 7.00% | 100.00% | 100.00% | 22.00% | 50.00% | 45.00% | 27.00% | 32.00% | 38.00% | 50.00% | 10.00% | 16.00% | |||||