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Derivative Financial Instruments Gains and Losses (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2016 | Jun. 30, 2015 | Jun. 30, 2016 | Jun. 30, 2015
Gain and loss from derivative cash settlements and changes in fair value of derivative contracts |  |  |  |  |
Derivative settlement gain (loss) |  | $ (101,710) | $ (112,795) | $ (248,738) | $ (274,024)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net |  | 163,351 | 80,929 | 149,123 | (73,238)
NYMEX Oil Contracts [Member] |  |  |  |  |
Gain and loss from derivative cash settlements and changes in fair value of derivative contracts |  |  |  |  |
Derivative settlement gain (loss) |  | (72,164) | (73,915) | (172,156) | (180,129)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net |  | 60,773 | 66,749 | 50,341 | (7,111)
Gas Contracts [Member] |  |  |  |  |
Gain and loss from derivative cash settlements and changes in fair value of derivative contracts |  |  |  |  |
Gain on Early Settlement of Derivatives |  |  | (15,300) |  |
Derivative settlement gain (loss) | [1] | (31,439) | (38,880) | (72,492) | (73,112)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net |  | 62,489 | 6,070 | 38,466 | (76,269)
NGL Contracts [Member] |  |  |  |  |
Gain and loss from derivative cash settlements and changes in fair value of derivative contracts |  |  |  |  |
Derivative settlement gain (loss) |  | 1,893 | 0 | (4,090) | (20,783)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net |  | $ 40,089 | $ 8,110 | $ 60,316 | $ 10,142
[1] | Natural gas derivative settlements for the three and six months ended June 30, 2015, include a $15.3 million gain on the early settlement of future contracts as a result of divesting our Mid-Continent assets during the second quarter of 2015.

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- Definition Gain on Early Settlement of Derivatives + 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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