Equity Method Investments - Operating Results (Details) - ICP [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Schedule of Equity Method Investments [Line Items]
Net sales	$ 44,019	$ 40,281	$ 134,204	$ 128,250
Cost of sales and expenses	41,805	35,072	126,671	107,851
Net income	$ 2,214	$ 5,209	$ 7,533	$ 20,399