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Derivative Financial Instruments (Details) (USD $) | 3 Months Ended
--- | ---
Mar. 31, 2013 | Mar. 31, 2012
Derivative Financial Instruments |  |
Fair value of oil, natural gas, NGL commodity derivative markets | $ (3,600,000) | $ 38,700,000
Derivative (gains) losses relating to de-designated commodity hedges reclassified from AOCL to earnings net of tax | 61,000 | (1,034,000)
Derivatives not designated as hedging instruments |  |
Derivative Financial Instruments |  |
Gains expected to be reclassifiied into earnings from AOCL after-tax net loss related to de-designated commodity derivative contracts | $ 1,100,000 |
Crude oil |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 13,000,000 |
Natural Gas |  |
Derivative Financial Instruments |  |
Portion of Gas Production Being Hedged | 119,000,000 |
Natural Gas Liquids |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 1,500,000 |

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- Definition Portion of Gas Production Being Hedged + References No definition available. + Details
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- Definition The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=7668309&loc=d3e80748-113994 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 45 -Subparagraph b(2) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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. + Details
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- Details
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- Definition The quantity of future oil and gas production being hedged. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section S99 -Paragraph 2 -Subparagraph (SAB TOPIC 12.D.3(b)) -URI http://asc.fasb.org/extlink&oid=6601679&loc=d3e516453-122869 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 12 -Section D -Paragraph b -Subsection 3 + Details
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- Definition The amount of net gains or losses on price risk cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income. + References No definition available. + Details
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- Definition Fair value as of the balance sheet date of price risk derivative assets, net of price risk derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized on the balance sheet. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13433-108611 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 17 -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 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13495-108611 + Details
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