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Contingencies (Details) (USD $)
In Millions, unless otherwise specified |
3 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
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Mar. 31, 2012
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Sep. 30, 2010
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Dec. 31, 2009
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Dec. 31, 2011
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| Contingencies [Abstract] | ||||
| Estimated contingency reserve change | $ 8.3 | |||
| Liability loss contingency | 10.3 | 2.0 | ||
| Allowable reductions of cash payments | (5.3) | |||
| Notified disallowed amount in reductions taken by ONRR | $ 4.7 | |||
| X | ||||||||||
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- Details
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| X | ||||||||||
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- Definition
The increase (decrease) during the reporting period in the obligations due for compensation payments related to the use of copyrights, patents, trade names, licenses, technology. Royalty payments are also paid by the lease holders for oil, gas, and mineral extraction. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Contested Royalty Adjustment. No definition available.
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| X | ||||||||||
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- Definition
Estimate Reserve Change No definition available.
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| X | ||||||||||
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- Definition
Liability Loss Contingency Environmental No definition available.
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