Goodwill, Long-lived Assets and Other Intangibles Goodwill (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 31, 2017 USD ($) ReportingUnits	Jul. 31, 2016 USD ($) ReportingUnits	Jul. 31, 2017 USD ($) ReportingUnits	Jul. 31, 2016 USD ($)	Jan. 31, 2016 USD ($) ReportingUnits
Goodwill [Line Items]
Number of Reporting Units | ReportingUnits	3	3	3		4
Number of reporting units in Aerostar Segment | ReportingUnits	1	1	1		2
Goodwill impairment loss	$ 0	$ 0	$ 0	$ 0
Goodwill [Roll Forward]
Goodwill Beginning balance			40,649	40,672
Goodwill, Written off Related to Sale of Business Unit			(52)
Goodwill, Foreign Currency Translation Gain (Loss)			244	80
Goodwill Ending balance	40,841	40,752	40,841	40,752	$ 40,672
Applied Technology [Member]
Goodwill [Roll Forward]
Goodwill Beginning balance			12,342	12,365
Goodwill, Written off Related to Sale of Business Unit			0
Goodwill, Foreign Currency Translation Gain (Loss)			244	80
Goodwill Ending balance	12,586	12,445	12,586	12,445	12,365
Engineered Films [Member]
Goodwill [Roll Forward]
Goodwill Beginning balance			27,518	27,518
Goodwill, Written off Related to Sale of Business Unit			0
Goodwill, Foreign Currency Translation Gain (Loss)			0	0
Goodwill Ending balance	27,518	27,518	27,518	27,518	27,518
Aerostar [Member]
Goodwill [Roll Forward]
Goodwill Beginning balance			789	789
Goodwill, Written off Related to Sale of Business Unit			(52)
Goodwill, Foreign Currency Translation Gain (Loss)			0	0
Goodwill Ending balance	$ 737	$ 789	$ 737	$ 789	$ 789