Inventories (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011
Inventory Disclosure [Abstract]
Raw materials	$ 27,096		$ 28,155
Work in process	3,691		2,757
Finished goods	3,400		2,065
Inventory, gross	34,187		32,977
Less: Allowance for excess and obsolete inventories	(804)	(537)	(363)	(300)	(300)	(300)
Total, net	$ 33,383		$ 32,614