Equity Method Investments - Operating Results (Details) - ICP [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Schedule of Equity Method Investments [Line Items]
Net sales	$ 40,281	$ 53,813	$ 128,250	$ 185,460
Cost of sales and expenses	35,072	48,467	107,851	155,214
Net income	$ 5,209	$ 5,346	$ 20,399	$ 30,246