Inventories (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Inventories [Abstract]
Raw materials	$ 17,478	$ 14,946
Work in progress	21,683	20,012
Manufactured and purchased components	22,136	18,702
Finished goods	32,102	30,988
Product inventory	93,399	84,648
Capitalized contract costs	11,501	5,391
Total inventories	$ 104,900	$ 90,039