Segment Reporting (Details) - USD ($) $ in Thousands		3 Months Ended		7 Months Ended		9 Months Ended
		Oct. 31, 2018	Oct. 31, 2017	Aug. 31, 2018	Aug. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Segment Reporting Information [Line Items]
Net sales		$ 104,833	$ 101,349			$ 318,646	$ 281,494
Administrative and general expenses	[1]	(7,166)	(5,990)			(24,388)	(17,247)
Operating income		13,612	17,829			51,772	47,748
Applied Technology [Member]
Segment Reporting Information [Line Items]
Net sales		29,740	25,319			100,532	94,233
Operating income		7,737	5,357			32,473	25,447
Engineered Films [Member]
Segment Reporting Information [Line Items]
Net sales	[2],[3]	58,239	65,108			177,106	157,691
Operating income		9,239	17,115			33,241	35,386
Engineered Films [Member] | Hurricane Recovery Film [Member]
Segment Reporting Information [Line Items]
Net sales		1,510	8,424			10,429	8,424
Aerostar [Member]
Segment Reporting Information [Line Items]
Net sales		17,031	11,103			41,449	30,078
Operating income		3,839	1,359			10,479	4,165
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	[4],[5]	(177)	(181)			(441)	(508)
Operating income		(37)	(12)			(33)	(3)
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Operating income		$ 20,778	$ 23,819			$ 76,160	$ 64,995
CLI [Member] | Engineered Films [Member]
Segment Reporting Information [Line Items]
Net sales				$ 21,568	$ 4,109

[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] Net sales includes $1,510 and $10,429 of recovery film sales for the three- and nine-month periods ended October, 31, 2018, respectively, related to hurricane recovery efforts. Fiscal year 2018 Net sales includes $8,424 of recovery film sales for the three- and nine-month periods ended October 31, 2017.

[3] The acquisition of CLI, which occurred in September of fiscal year 2018, contributed a total of $21,568 in sales for the first seven months of fiscal 2019. For the first seven months of fiscal 2018 the division generated $4,109 in sales to CLI as a customer. Refer to Note 6 "Acquisitions and Divestitures of and Investments in Businesses and Technologies" for further details on the acquisition of CLI.

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

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