Goodwill and Intangible Assets, Goodwill (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill
Goodwill	$ 37,200,000	$ 37,200,000
Goodwill impairment	0
Fabricated Products
Goodwill
Goodwill	37,200,000	37,200,000
Customer relationships
Goodwill
Finite-Lived Intangible Assets, Gross	$ 38,500,000	$ 38,500,000