Derivative Instruments And Hedging Activities Derivatives and Hedging Instruments Gains Losses due to Settlements Hedge Ineffectiveness (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Trading Activity, Gains and Losses, Net [Line Items]
Change in fair value	$ (5,138)	$ 8,501	$ (17,059)	$ (5,647)
(Gain) loss reclassified to earnings due to settlements	21,910	(14,802)	32,966	(19,494)
Amortization of discontinued hedges reclassified to earnings	270	270	540	540
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	17,042	(6,031)	16,447	(24,601)
Gain (Loss) Recognized in Earnings due to Settlements	(22,180)	14,532	(33,506)	18,954
Gain (Loss) Attributable to Hedge Ineffectiveness Recognized in Earnings	0	2,354	0	4,011
Sales [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) Attributable to Hedge Ineffectiveness Recognized in Earnings		(140)		(274)
Cost of Sales [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) Attributable to Hedge Ineffectiveness Recognized in Earnings	0	2,494		3,738
Operating Expense [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) Attributable to Hedge Ineffectiveness Recognized in Earnings			0	547
Commodity Contract [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Sales [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) Recognized in Earnings due to Settlements		49,752		98,932
Commodity Contract [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Cost of Sales [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) Recognized in Earnings due to Settlements	(15,897)	(30,964)	(20,653)	(71,733)
Commodity Contract [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Operating Expense [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) Recognized in Earnings due to Settlements	$ (6,283)	$ (4,256)	$ (12,853)	$ (8,245)

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624177-113959

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The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

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Amount of gain (loss) from the ineffectiveness of the hedge.

+ 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 (d)(1)
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-Publisher FASB
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-Section 50
-Paragraph 1
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Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
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-Section 50
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The amount of net gain (loss) reclassified into earnings in the period when cash flow hedge is discontinued because it is probable that the original forecasted transactions will not occur by the end of the original period or an additional two month time period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 30
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-Paragraph 1
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Amount of unrealized gain (loss) related to derivatives designated as cash flow hedging instruments, recorded in results of operations to the extent that the cash flow hedge is determined to be ineffective.

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