Segment Reporting (Details) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
		Jul. 31, 2016		Jul. 31, 2015		Jul. 31, 2016		Jul. 31, 2015
Segment Reporting Information [Line Items]
Net sales		$ 67,598		$ 67,518		$ 135,958		$ 137,791
Operating income		6,696		6,429		14,746		13,643
Administrative and general expenses		(4,884)		(4,316)		(9,222)		(9,520)
Applied Technology [Member]
Segment Reporting Information [Line Items]
Gain (Loss) on Disposition of Assets		161		247		161		611
Net sales		22,668		20,411		54,124		52,821
Operating income		5,172	[1]	4,041	[2]	13,865	[1]	12,782	[2]
Engineered Films [Member]
Segment Reporting Information [Line Items]
Net sales		36,656		35,789		65,756		67,110
Operating income		6,659		5,365		10,537		9,836
Aerostar Division [Member]
Segment Reporting Information [Line Items]
Gain (Loss) on Disposition of Assets				(70)				(70)
Net sales		8,415		11,328		16,310		17,882
Operating income		(251)		1,314	[3]	(429)		461	[3]
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	[4]	(141)		(10)		(232)		(22)
Operating income	[4]	0		25		(5)		84
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Operating income		$ 11,580		$ 10,745		$ 23,968		$ 23,163

[1] (b) Includes $161 gain for both the three- and six-month periods ended July 31, 2016 on the disposal of an idle manufacturing plant held for sale.

[2] (c) Includes gains of $247 and $611 for the three- and six-month periods ended July 31, 2015, respectively, on disposal of assets related to the exit of contract manufacturing operations.

[3] (d) Includes ($70) loss for both the three- and six-month periods ended July 31, 2015 on disposal of an idle manufacturing plant held for sale.

[4] (a) Intersegment sales for both fiscal 2017 and 2016 were primarily sales from Engineered Films to Aerostar.