Segment Reporting (Details) - USD ($) $ in Thousands		3 Months Ended
		Apr. 30, 2018	Apr. 30, 2017
Segment Reporting Information [Line Items]
Net sales		$ 111,129	$ 93,535
Operating income		21,531	18,219
Administrative and general expenses		(10,403)	(5,370)
Applied Technology [Member]
Segment Reporting Information [Line Items]
Net sales		40,430	40,490
Operating income	[1]	15,948	13,453
Engineered Films [Member]
Segment Reporting Information [Line Items]
Net sales	[2]	59,992	43,555
Operating income	[1]	13,196	8,720
Engineered Films [Member] | Hurricane Recovery Film [Member]
Segment Reporting Information [Line Items]
Net sales		8,919	0
Aerostar [Member]
Segment Reporting Information [Line Items]
Net sales		10,901	9,606
Operating income	[1]	2,805	1,418
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	[3],[4]	(194)	(116)
Operating income	[4]	(15)	(2)
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Operating income		31,934	23,589
CLI [Member] | Engineered Films [Member]
Segment Reporting Information [Line Items]
Net sales		$ 7,744	$ 0

[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] Fiscal year 2019 Net sales includes $7,744 in net sales related to the CLI asset acquisition further described in Note 6 "Acquisitions and Divestitures of and Investments in Businesses and Technologies", and $8,919 of recovery film sales related to the hurricane recovery effort.

[3] Intersegment sales for both fiscal 2019 and 2018 were primarily sales from Engineered Films to Aerostar.

[4] Intersegment sales for both fiscal 2019 and 2018 were primarily sales from Engineered Films to Aerostar.