Joint Venture - Operating Results (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Schedule of Equity Method Investments [Line Items]
Net sales	$ 130,692	$ 166,328	$ 294,540	$ 354,868
Cost of materials	97,644	152,179	231,402	296,534
Net (Loss) Income	(21,270)	(46,252)	(58,140)	(61,379)
Joint venture
Schedule of Equity Method Investments [Line Items]
Net sales	29,752	41,014	61,270	93,620
Cost of materials	25,155	35,045	51,756	79,395
Income (loss) before taxes	(65)	760	501	2,750
Net (Loss) Income	$ 368	$ 902	$ 990	$ 2,652