Derivative Instruments and Hedging Activities Derivatives and Hedging Instruments Gains Losses due to Settlements Hedge Ineffectiveness (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Trading Activity, Gains and Losses, Net [Line Items]
Unrealized Gain (Loss) on Cash Flow Hedging Instruments	$ 14,538	$ 25,139	$ (52,495)
Change in Fair Value	2,831	(17,018)	(3,983)
Gain (Loss) Reclassified to Earnings due to Settlements	10,627	41,077	(49,592)
Amortization of discontinued hedges reclassified to earnings	1,080	1,080	1,080
Gain (Loss) recognized in earnings due to settlements	(11,707)	(42,157)	48,512
Derivative, Net Hedge Ineffectiveness Gain (Loss)	(54)	0	4,649
Sales [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) recognized in earnings due to settlements	7,836	(20,293)	245,819
Derivative, Net Hedge Ineffectiveness Gain (Loss)			(274)
Cost of products sold
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) recognized in earnings due to settlements	(299)		(179,700)
Derivative, Net Hedge Ineffectiveness Gain (Loss)			4,376
Operating expenses
Trading Activity, Gains and Losses, Net [Line Items]
Gain (Loss) recognized in earnings due to settlements	(19,244)	(21,864)	(17,607)
Derivative, Net Hedge Ineffectiveness Gain (Loss)	$ (54)	$ 0	$ 547

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=84234895&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=84234895&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.

+ References

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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=84234895&loc=SL5624171-113959

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-Publisher FASB
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-Section 50
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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
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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
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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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