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Supplemental Oil And Gas Disclosures (Results Of Operations For Oil And Natural Gas Producing Activities) (Details) (USD $) In Thousands, unless otherwise specified | 12 Months Ended
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Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2009 contracts
Supplemental Oil And Gas Disclosures [Abstract] |  |  |  |  |  |
Revenues | $ 330,422 |  | $ 128,927 |  | $ 37,755 |
Production costs | 67,937 |  | 28,350 |  | 12,501 |
Depreciation, depletion and amortization | 74,101 |  | 37,583 |  | 16,592 |
Exploration costs | 1,685 |  | 297 |  | 1,019 |
Rig termination |  | [1] |  | [1] | 3,000 | [1]
Impairment of oil and gas properties | 3,610 |  | 11,967 |  | 6,233 |
Gain (Loss) on Sale of Property | (207) |  |  |  | 1,455 |
Loss on sale of properties | (207) |  |  |  | 1,455 |
Loss (gain) on sale of properties | 207 |  |  |  | (1,455) |
Income tax expenses | 64,009 |  | 17,756 |  |  |
Results of operations for oil and gas producing activities | $ 118,873 |  | $ 32,974 |  | $ (135) |
Number of drilling rig contracts terminated during the period. |  |  |  |  | 2 |
[1] | During the first quarter of 2009, we paid a total of $3.0 million in rig termination expenses in connection with early termination of two drilling rig contracts entered into in 2008. We did not have any rig termination expenses during the years ended December 31, 2011 and 2010.

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- Definition Gain (loss) recognized on the sale of oil and gas property or timber property. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585 + Details
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- Definition Depreciation, depletion and amortization, and valuation provisions (impairments) related to oil and gas producing activities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 19 -Paragraph 59S -Subparagraph d -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 23 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6821537&loc=d3e62136-109447 + Details
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