Segment Reporting (Details) - USD ($) $ in Thousands		3 Months Ended
		Apr. 30, 2019	Apr. 30, 2018
Segment Reporting Information [Line Items]
Net sales		$ 98,178	$ 111,129
Administrative and general expenses	[1]	(6,475)	(10,403)
Operating income		15,121	21,531
Applied Technology [Member]
Segment Reporting Information [Line Items]
Net sales		41,725	40,430
Operating income		13,236	15,948
Engineered Films [Member]
Segment Reporting Information [Line Items]
Net sales	[2]	44,292	59,992
Operating income		6,363	13,196
Engineered Films [Member] | Hurricane Recovery Film [Member]
Segment Reporting Information [Line Items]
Net sales		17	8,919
Aerostar [Member]
Segment Reporting Information [Line Items]
Net sales		12,190	10,901
Operating income		1,996	2,805
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	[3]	(29)	(194)
Operating income		1	(15)
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Operating income		$ 21,596	$ 31,934

[1] At the segment level, operating income does not include an allocation of general and administrative expenses and, as a result, "General and administrative expenses" are reported as a deduction from "Total reportable segment income" to reconcile to "Operating income" reported in the Consolidated Statements of Income and Comprehensive Income.

[2] Hurricane recovery film sales for the three-month period ended April 30, 2019 and 2018, were $17 and $8,919, respectively.

[3] Intersegment sales for both fiscal 2020 and 2019 were primarily sales from Engineered Films to Aerostar.