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Property and Equipment (Narrative) (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2016 | Sep. 30, 2015 | Sep. 30, 2016 | Sep. 30, 2015 | Dec. 31, 2015
Property, Plant and Equipment [Line Items] |  |  |  |  |
Impairment of properties under the full cost method of accounting | $ 212,194 | $ 594,776 | $ 601,806 | $ 594,776 |
Cumulative capitalization of general and administrative costs incurred and capitalized to the full cost pool | 122,800 |  | 122,800 |  |
Capitalized general and administrative costs | 7,200 | $ 7,300 | 22,200 | $ 20,800 |
Capitalized costs of oil and natural gas properties excluded from amortization | $ 1,723,821 |  | $ 1,723,821 |  | $ 1,817,701
Non-producing leases, extension term |  |  | 5 years |  |
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 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 Term of the lessee's leasing arrangement renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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