Goodwil, Long-lived Assets, and Other Charges - Inventory Write Downs (Details) - Cost of Sales - USD ($)	3 Months Ended	12 Months Ended
	Oct. 31, 2016	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Schedule of Inventory write-down [Line Items]
Inventory write-down		$ 0	$ 0	$ 2,278,000
Radar Inventory | Aerostar
Schedule of Inventory write-down [Line Items]
Inventory write-down	$ 2,278,000			$ 2,278,000