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Derivative Financial Instruments Gains and Losses (Details) - USD ($) $ in Thousands | 3 Months Ended
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Mar. 31, 2016 | Mar. 31, 2015
Gain and loss from derivative cash settlements and changes in fair value of derivative contracts |  |
Derivative settlement gain (loss) | $ (147,028) | $ (161,229)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net | (14,228) | (154,167)
NYMEX Oil Contracts [Member] |  |
Gain and loss from derivative cash settlements and changes in fair value of derivative contracts |  |
Derivative settlement gain (loss) | (99,992) | (106,214)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net | (10,432) | (73,860)
Gas Contracts [Member] |  |
Gain and loss from derivative cash settlements and changes in fair value of derivative contracts |  |
Derivative settlement gain (loss) | (41,053) | (34,232)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net | (24,023) | (82,339)
NGL Contracts [Member] |  |
Gain and loss from derivative cash settlements and changes in fair value of derivative contracts |  |
Derivative settlement gain (loss) | (5,983) | (20,783)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net | $ 20,227 | $ 2,032

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959 + Details
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