Goodwill, Long-lived Assets and Other Intangibles Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017
Goodwill [Line Items]
Goodwill impairment loss	$ 0	$ 0	$ 0	$ 0
Goodwill [Roll Forward]
Goodwill Beginning balance			46,710
Divestiture of business			(103)
Goodwill, Foreign Currency Translation Gain (Loss)			(169)
Goodwill Ending balance	46,438		46,438
Applied Technology [Member]
Goodwill [Roll Forward]
Goodwill Beginning balance			12,741
Divestiture of business			0
Goodwill, Foreign Currency Translation Gain (Loss)			(169)
Goodwill Ending balance	12,572		12,572
Engineered Films [Member]
Goodwill [Roll Forward]
Goodwill Beginning balance			33,232
Divestiture of business			0
Goodwill, Foreign Currency Translation Gain (Loss)			0
Goodwill Ending balance	33,232		33,232
Aerostar [Member]
Goodwill [Roll Forward]
Goodwill Beginning balance			737
Divestiture of business			(103)
Goodwill, Foreign Currency Translation Gain (Loss)			0
Goodwill Ending balance	$ 634		$ 634