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%