Inventories (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Inventory Disclosure [Abstract]
Raw materials	$ 32,750		$ 28,592
Work in process	2,267		2,286
Finished goods	2,326		1,841
Inventory, gross	37,343		32,719
Less: Allowance for excess and obsolete inventories	(735)	(583)	(579)	(537)	(532)	(363)
Total, net	$ 36,608		$ 32,140