Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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Percentage Of Natural Gas Purchases For Which The Companys Exposure To Fluctuations In Gas Prices Have Been Reduced.

+ References

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Percentage of Electricity Purchases For Which The Company's Exposure To Fluctuations In Electricity Prices Have Been Reduced

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- Definition

Nominal or face amount used to calculate payments on the derivative liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Notional Amount
-URI http://asc.fasb.org/extlink&oid=6519104

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5579245-113959

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No definition available.

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Derivative Financial Instruments and Related Hedging Programs, Material Derivative Positions (Details)	Jun. 30, 2016 EUR (€) MMBTU mmlbs	Dec. 31, 2015 EUR (€)
Remainder of 2016
Derivative [Line Items]
Percentage of natural gas purchases for which the Company's exposure to fluctuations in gas prices had been substantially reduced	81.00%
Percentage of Electricity Purchases For Which Company Exposure To Fluctuations In Electricity Prices Have Been Reduced	55.00%
2017
Derivative [Line Items]
Percentage of natural gas purchases for which the Company's exposure to fluctuations in gas prices had been substantially reduced	74.00%
Percentage of Electricity Purchases For Which Company Exposure To Fluctuations In Electricity Prices Have Been Reduced	54.00%
2018
Derivative [Line Items]
Percentage of natural gas purchases for which the Company's exposure to fluctuations in gas prices had been substantially reduced	72.00%
Percentage of Electricity Purchases For Which Company Exposure To Fluctuations In Electricity Prices Have Been Reduced	36.00%
Not Designated as Hedging Instrument \| Aluminum \| Fixed priced contracts \| Purchase
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	182.5
Not Designated as Hedging Instrument \| Aluminum \| Fixed priced contracts \| Sales
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0.9
Not Designated as Hedging Instrument \| Aluminum \| Midwest premium swap contracts \| Purchase
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	157.1
Not Designated as Hedging Instrument \| Natural Gas \| Fixed priced contracts \| Purchase
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount \| MMBTU	5,950,000
Designated as Hedging Instrument [Member] \| Foreign Currency Member \| Fixed priced contracts \| Purchase
Derivative [Line Items]
Notional amount of contracts \| €	€ 2,020,950	€ 4,700,000