Other Balance Sheet Information - Summary of Inventories (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Raw materials and purchased parts	$ 83,603	$ 73,819
Work-in-process	21,699	10,548
Finished goods	26,996	22,028
Inventory, net	132,298	106,395
Reserves for excess and obsolete inventory	$ 21,000	$ 23,500