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Segment Information, Supply Information (Details) - Supplier Concentration Risk - Aluminum | 3 Months Ended
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Mar. 31, 2016 | Mar. 31, 2015
Top five major suppliers |  |
Concentration Risk |  |
Concentration Risk, Percentage | 83.00% | 75.00%
Largest supplier |  |
Concentration Risk |  |
Concentration Risk, Percentage | 30.00% | 29.00%
Second and third largest suppliers |  |
Concentration Risk |  |
Concentration Risk, Percentage | 35.00% | 29.00%

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