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Financial Instruments (Narrative) (Details) lb in Millions, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2016 USD ($) lb | Dec. 31, 2015 USD ($) lb
Derivative [Line Items] |  |
Weight of aluminum that hedged future purchase of aluminum to meet fixed-price forward sales contract obligations, lbs | lb | 9.6 | 18.9
Amounts of unrealized after-tax gains on derivative instruments | $ 0.2 |
Aluminum Futures Contracts |  |
Derivative [Line Items] |  |
Notional amount | $ 8.0 | $ 16.6

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- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References 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 + Details
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- Definition The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months. + 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 (c) -URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Nominal mass used to calculate payments on a derivative instrument. + References No definition available. + Details
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- Details
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