Goodwil, Long-lived Assets, and Other Charges - Long-lived Asset Impairment (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Oct. 31, 2016	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Impaired Long-Lived Assets Held and Used [Line Items]
Long-lived asset impairment loss		$ 0	$ 259	$ 87
Finite-lived intangible assets, net		16,293	10,584
Patented Technology
Impaired Long-Lived Assets Held and Used [Line Items]
Finite-lived intangible assets, net		4,023	1,860
Operating Income (Loss)
Impaired Long-Lived Assets Held and Used [Line Items]
Long-lived asset impairment loss		$ 0	$ 259	87
Aerostar | Lighter than Air asset group
Impaired Long-Lived Assets Held and Used [Line Items]
Long-lived assets excess of fair value over carrying value	$ 110,000
Long-lived asset, percentage fair value exceeds carrying value	800.00%
Aerostar | Radar Technology and Radar Customers
Impaired Long-Lived Assets Held and Used [Line Items]
Long-lived assets, fair value	$ 175
Finite-lived intangible assets, net	262
Aerostar | Patented Technology
Impaired Long-Lived Assets Held and Used [Line Items]
Long-lived asset impairment loss	25			25
Aerostar | Property, Plant and Equipment
Impaired Long-Lived Assets Held and Used [Line Items]
Long-lived asset impairment loss	62			62
Aerostar | Operating Income (Loss) | Radar Technology and Radar Customers
Impaired Long-Lived Assets Held and Used [Line Items]
Long-lived asset impairment loss	$ 87			$ 87