Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Raw materials	$ 36,571		$ 34,153
Work in process	2,684		2,262
Finished goods	2,400		1,917
Inventory, gross	41,655		38,332
Less: Allowance for excess and obsolete inventories	(603)	$ (773)	(714)	$ (802)	$ (735)	$ (579)
Total, net	$ 41,052		$ 37,618