Segment Reporting (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017
Segment Reporting Information [Line Items]
Net sales		$ 102,684	$ 86,610	$ 213,813	$ 180,145
Administrative and general expenses	[1]	(6,819)	(5,887)	(17,222)	(11,257)
Operating income		16,629	11,700	38,160	29,919
Applied Technology [Member]
Segment Reporting Information [Line Items]
Net sales		30,362	28,424	70,792	68,914
Operating income		8,788	6,637	24,736	20,090
Engineered Films [Member]
Segment Reporting Information [Line Items]
Net sales	[2]	58,875	49,028	118,867	92,583
Operating income		10,806	9,551	24,002	18,271
Engineered Films [Member] | Hurricane Recovery Film [Member]
Segment Reporting Information [Line Items]
Net sales		0	0	8,919	0
Aerostar [Member]
Segment Reporting Information [Line Items]
Net sales		13,517	9,369	24,418	18,975
Operating income		3,835	1,388	6,640	2,806
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	[3],[4]	(70)	(211)	(264)	(327)
Operating income		19	11	4	9
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Operating income		23,448	17,587	55,382	41,176
CLI [Member] | Engineered Films [Member]
Segment Reporting Information [Line Items]
Net sales		$ 10,276	$ 1,283	$ 18,373	$ 3,608

[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 approximately $10,276 and $18,373 in net sales for the three- and six-month periods ended July 31, 2018, respectively, related to the CLI acquisition further described in Note 6 "Acquisitions and Divestitures of and Investments in Businesses and Technologies". The division generated $1,283 and $3,608 in sales to CLI for the three- and six-month periods ended July 31, 2017, respectively. Fiscal year 2019 Net sales includes $0 and $8,919 of recovery film sales for the three- and six-month periods ended July, 31, 2018, respectively, related to the hurricane recovery effort. No hurricane recovery film sales occurred during the three- and six-month periods ended July 31, 2017.

[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.