Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Segment Reporting Information [Line Items]
Net sales	$ 100,533	$ 104,833	$ 296,769	$ 318,646
Administrative and general expenses	(6,653)	(7,166)	(20,501)	(24,388)
Operating income	11,332	13,612	37,023	51,772
Applied Technology [Member]
Segment Reporting Information [Line Items]
Net sales	28,500	29,740	97,596	100,532
Operating income	7,035	7,737	25,120	32,473
Engineered Films [Member]
Segment Reporting Information [Line Items]
Net sales	56,406	58,239	158,214	177,106
Operating income	8,474	9,239	24,987	33,241
Engineered Films [Member] | Hurricane Recovery Film [Member]
Segment Reporting Information [Line Items]
Net sales	1,833		10,429
Aerostar [Member]
Segment Reporting Information [Line Items]
Net sales	15,661	17,031	41,040	41,449
Operating income	2,488	3,839	7,427	10,479
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	(34)	(177)	(81)	(441)
Operating income	(12)	(37)	(10)	(33)
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Net sales	100,533	104,833	296,769	318,646
Operating income	$ 17,985	$ 20,778	$ 57,524	$ 76,160