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Property And Equipment (Narrative) (Details) - USD ($) | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2016 | Jun. 30, 2015 | Jun. 30, 2016 | Jun. 30, 2015 | Dec. 31, 2015
Property, Plant and Equipment [Line Items] |  |  |  |  |
Impairment of oil and gas properties | $ 170,621,000 | $ 0 | $ 389,612,000 | $ 0 |
Cumulative capitalization of general and administrative costs incurred and capitalized to the full cost pool | 115,600,000 |  | 115,600,000 |  |
Capitalized general and administrative costs | 7,900,000 | $ 6,300,000 | 15,000,000 | $ 13,500,000 |
Capitalized costs of oil and natural gas properties excluded from amortization | $ 1,762,439,000 |  | $ 1,762,439,000 |  | $ 1,817,701,000
Minimum |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Expected number of years amortization will commence |  |  | 3 years |  |
Maximum |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Expected number of years amortization will commence |  |  | 5 years |  |

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- Definition Cumulative capitalization of general and administrative costs incurred and capitalized to the full cost pool. + References No definition available. + Details
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- Definition The sum of the capitalized costs incurred, as of the balance sheet date, of unproved properties excluded from amortization including acquisition costs, exploration costs, development costs, and production costs. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-10.(c)(7)(ii)) -URI http://asc.fasb.org/extlink&oid=50486907&loc=d3e511914-122862 + Details
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- Definition The expense recorded to reduce the value of oil and gas assets consisting of proved properties and unproved properties as the estimate of future successful production from these properties is reduced. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51719941&loc=d3e2921-110230 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 35 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=28370743&loc=d3e66150-109466 Reference 3: 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=56944662&loc=d3e3602-108585 + Details
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