Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Raw materials	$ 43,438	$ 33,853
Work in process	2,279	2,522
Finished goods	3,017	2,881
Inventory, gross	48,734	39,256
Less: Allowance for excess and obsolete inventories	(1,382)	(757)	$ (714)	$ (579)
Total, net	$ 47,352	$ 38,499