Segment Reporting (Details) - USD ($) $ in Thousands		3 Months Ended
		Apr. 30, 2016	Apr. 30, 2015
Segment Reporting Information [Line Items]
Net sales		$ 68,360	$ 70,273
Operating income		7,607	7,214
Administrative and general expenses		(4,338)	(5,204)
Applied Technology [Member]
Segment Reporting Information [Line Items]
Net sales		31,456	32,410
Operating income		8,693	8,741
Engineered Films [Member]
Segment Reporting Information [Line Items]
Net sales		29,100	31,321
Operating income		3,878	4,471
Aerostar Division [Member]
Segment Reporting Information [Line Items]
Net sales		7,895	6,554
Operating income		(621)	(853)
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	[1]	(91)	(12)
Operating income	[1]	(5)	59
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Operating income		$ 11,945	$ 12,418

[1] (a) Intersegment sales for both fiscal 2017 and 2016 were primarily sales from Engineered Films to Aerostar.