Derivative Instruments And Hedging Activities Derivatives and Hedging Instruments Gains Losses due to Settlements Hedge Ineffectiveness (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Trading Activity, Gains and Losses, Net [Line Items]
Change in fair value, effective portion	$ (11,921)	$ (14,148)
Gain reclassified to earnings due to settlements	11,056	(4,692)
Amortization of discontinued hedges reclassified to earnings	270	270
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	(595)	(18,570)
Gain (Loss) Recognized in Earnings due to Settlements	(11,326)	4,422
Gain (Loss) Attributable to Hedge Ineffectiveness Recognized in Earnings		1,658
Sales [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) Attributable to Hedge Ineffectiveness Recognized in Earnings		(133)
Cost of Sales [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) Attributable to Hedge Ineffectiveness Recognized in Earnings		1,244
Operating Expense [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) Attributable to Hedge Ineffectiveness Recognized in Earnings		547
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] \| 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	(4,756)	49,180
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] \| 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		(40,769)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] \| 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	$ (6,570)	$ (3,989)

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)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

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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
-SubTopic 10
-Section 50
-Paragraph 4A
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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
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (e)
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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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