Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Segment Reporting Information [Line Items]
Net sales	$ 96,607	$ 100,533	$ 268,282	$ 296,769
Administrative and general expenses	(6,613)	(6,653)	(20,148)	(20,501)
Operating income	9,291	11,332	19,373	37,023
Applied Technology [Member]
Segment Reporting Information [Line Items]
Net sales	34,838	28,500	112,347	97,596
Operating income	5,797	7,035	21,247	25,120
Engineered Films [Member]
Segment Reporting Information [Line Items]
Net sales	43,765	56,406	113,415	158,214
Operating income	7,321	8,474	13,393	24,987
Aerostar [Member]
Segment Reporting Information [Line Items]
Net sales	18,010	15,661	42,626	41,040
Operating income	2,777	2,488	4,821	7,427
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	(6)	(34)	(106)	(81)
Operating income	9	(12)	60	(10)
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Net sales	96,607	100,533	268,282	296,769
Operating income	$ 15,904	$ 17,985	$ 39,521	$ 57,524