Inventories (Schedule of Inventory, Current) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Finished goods and parts	$ 133,161	$ 116,667
Work in process	10,243	9,431
Raw materials	12,164	9,662
Inventory, net	$ 155,568	$ 135,760