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Segment and Geographical Area Information Segment and Geographical Area Information, Schedules of Concentration of Risk, by Risk Factor (Details) | 12 Months Ended
--- | ---
Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Export sales | Net sales |  |  |
Concentration Risk |  |  |
Concentration risk, percentage | 19.00% | 19.00% | 17.00%
Supplier concentration risk | Aluminum | Top five major suppliers |  |  |
Concentration Risk |  |  |
Concentration risk, percentage | 86.00% | 71.00% | 86.00%
Supplier concentration risk | Aluminum | Largest supplier |  |  |
Concentration Risk |  |  |
Concentration risk, percentage | 28.00% | 30.00% | 25.00%
Supplier concentration risk | Aluminum | Second and third largest suppliers |  |  |
Concentration Risk |  |  |
Concentration risk, percentage | 36.00% | 25.00% | 35.00%

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