Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Finished goods	$ 30,654	$ 34,298	$ 32,249
Parts and materials	10,790	10,817	9,147
Work in progress	3,018	2,470	1,975
Total inventories	$ 44,462	$ 47,585	$ 43,371