Inventories (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Raw materials	$ 36,442		$ 33,853
Work in process	2,417		2,522
Finished goods	2,331		2,881
Inventory, gross	41,190		39,256
Less: Allowance for excess and obsolete inventories	(1,065)	$ (894)	(757)	$ (773)	$ (755)	$ (714)
Total, net	$ 40,125		$ 38,499