Inventories - Charges Associated With the Valuation of Inventory (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Inventory, net	$ 6,120	$ 1,447	$ 2,539
Adverse purchase commitments	(1,908)	1,831	323
Net charges	$ 4,212	$ 3,278	$ 2,862