Inventories (Details) (USD $) In Thousands, unless otherwise specified	Mar. 30, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Raw materials and assembled parts	$ 62,191	$ 61,235
Service inventories, estimated current requirements	14,516	15,197
Work-in-process	84,187	75,883
Finished goods	31,657	29,410
Total current inventories	192,551	181,725
Non-current inventories	$ 59,295	$ 62,104