Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 30, 2014		Apr. 30, 2013
Segment Reporting Information [Line Items]
Net sales	$ 102,510		$ 103,680
Operating income	16,532		20,934
Administrative and general expenses	(5,260)		(4,762)
Applied Technology Division [Member]
Segment Reporting Information [Line Items]
Net sales	46,288		51,181
Operating income	15,856		19,157
Engineered Films Division [Member]
Segment Reporting Information [Line Items]
Net sales	42,207		34,493
Operating income	5,863		4,754
Aerostar Division [Member]
Segment Reporting Information [Line Items]
Net sales	17,665		21,715
Operating income	11		1,806
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	(3,650)	[1]	(3,709)	[1]
Operating income	62	[1]	(21)	[1]
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Operating income	$ 21,792		$ 25,696

[1] Intersegment sales were primarily from Aerostar to Applied Technology.