Joint Venture - Operating Results (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Schedule of Equity Method Investments [Line Items]
Net sales	$ 249,492	$ 273,410	$ 502,902	$ 566,124
Cost of materials	191,565	201,461	380,096	420,892
Income (loss) before taxes	(78,395)	(11,614)	(94,444)	(23,605)
Net Income (Loss)	(72,298)	(3,799)	(88,296)	(14,421)
Joint venture
Schedule of Equity Method Investments [Line Items]
Net sales	62,608	57,451	127,859	114,780
Cost of materials	52,100	48,152	106,403	96,371
Income (loss) before taxes	4,639	3,695	9,443	7,051
Net Income (Loss)	$ 3,588	$ 2,988	$ 7,402	$ 5,926