Goodwil, Long-lived Assets, and Other Charges - Inventory Write Downs and Pre-Contract Costs Write Downs (Details) - Cost of Sales - USD ($)	3 Months Ended			12 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Schedule of Inventory write-down [Line Items]
Inventory write-down				$ 0	$ 2,278,000	$ 0
Pre-contract deferred costs written off				$ 0	0	$ 2,933,000
Vista Research
Schedule of Inventory write-down [Line Items]
Pre-contract deferred costs written off		$ 2,933,000
Amount of deferred costs related to long-term contracts		$ 858,000	$ 2,075,000
Radar Inventory | Aerostar
Schedule of Inventory write-down [Line Items]
Inventory write-down	$ 2,278,000
Radar Inventory | Vista Research
Schedule of Inventory write-down [Line Items]
Inventory write-down					$ 2,278,000