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Significant Accounting Policies (Percentage Of Revenue By Major Customers) (Details)
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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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| Revenue, Major Customer [Line Items] | ||||||||
| Percentage of receipts | 10.00% | |||||||
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Shell Trading (US) Co. [Member]
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| Revenue, Major Customer [Line Items] | ||||||||
| Percentage of receipts | 36.00% | 40.00% | 34.00% | |||||
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ConocoPhillips [Member]
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| Revenue, Major Customer [Line Items] | ||||||||
| Percentage of receipts | 16.00% | 17.00% | [1] | |||||
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J.P. Morgan Ventures Energy Corp. [Member]
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| Revenue, Major Customer [Line Items] | ||||||||
| Percentage of receipts | 10.00% | [1] | 15.00% | |||||
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Chevron Corp. [Member]
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| Revenue, Major Customer [Line Items] | ||||||||
| Percentage of receipts | [1] | [1] | 13.00% | |||||
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