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Segment Information, Narrative (Details) - productionfacilities | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2016 | Mar. 31, 2015 | Dec. 31, 2015
Segment Reporting Information |  |  |
Percentage of Employees Covered by Collective Bargaining Agreements | 63.00% |  |
Percentage of Employees Covered by Collective Bargaining Agreements Expiring Within One Year | 6.00% |  |
United States |  |  |
Segment Reporting Information |  |  |
Number of production facilities | 11 |  |
Canada |  |  |
Segment Reporting Information |  |  |
Number of production facilities | 1 |  |
Customer Concentration Risk | Largest Customer | Sales Revenue, Net | Fabricated Products |  |  |
Segment Reporting Information |  |  |
Concentration Risk, Percentage | 25.00% | 23.00% |
Customer Concentration Risk | Largest Customer | Accounts Receivable |  |  |
Segment Reporting Information |  |  |
Concentration Risk, Percentage | 19.00% |  |
Customer Concentration Risk | Second Largest Customer | Sales Revenue, Net | Fabricated Products |  |  |
Segment Reporting Information |  |  |
Concentration Risk, Percentage | 10.00% | 10.00% |
Customer Concentration Risk | Second Largest Customer | Accounts Receivable |  |  |
Segment Reporting Information |  |  |
Concentration Risk, Percentage | 12.00% |  | 17.00%

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