Goodwill and Long-Lived Asset Impairment Loss and Other Charges (Long-lived Asset Impairment) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2015	Oct. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Long-lived asset impairment loss	$ 3,813	$ 0	$ 3,813	$ 0
Accumulated long-lived intangible impairment losses	3,813	$ 0	3,813	$ 0
Vista Reporting Unit [Member]
Finite-Lived Intangible Assets [Line Items]
Long-lived assets, fair value	103		103
Long-lived assets, carrying value	3,916		3,916
Long-lived asset impairment loss	3,813		3,813
Vista Reporting Unit [Member] | Property, Plant and Equipment [Member]
Finite-Lived Intangible Assets [Line Items]
Long-lived asset impairment loss	554		554
Vista Reporting Unit [Member] | Radar Technology and Radar Customers [Member]
Finite-Lived Intangible Assets [Line Items]
Long-lived asset impairment loss	3,154		3,154
Vista Reporting Unit [Member] | Patented Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Long-lived asset impairment loss	$ 105		$ 105