Revenue Disaggregation of Revenue (Details) - USD ($) $ in Thousands		3 Months Ended
		Apr. 30, 2018	Apr. 30, 2017
Disaggregation of Revenue [Line Items]
Net sales		$ 111,129	$ 93,535
Lighter-than-air [Member]
Disaggregation of Revenue [Line Items]
Domestic Net Sales		6,548	6,206
International Net Sales		454	26
Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Domestic Net Sales		55,103	40,995
International Net Sales		4,695	2,444
Precision Agriculture [Member]
Disaggregation of Revenue [Line Items]
Domestic Net Sales		29,525	30,259
International Net Sales		10,905	10,231
Product [Member]
Disaggregation of Revenue [Line Items]
Domestic Net Sales		3,899	3,332
International Net Sales		0	42
Engineered Films Plastic Films & Sheeting [Member]
Disaggregation of Revenue [Line Items]
Domestic Net Sales		55,297	41,111
International Net Sales		4,695	2,444
Net sales		59,992	43,555
Applied Technology Precision Agriculture Equipment [Member]
Disaggregation of Revenue [Line Items]
Domestic Net Sales		29,525	30,259
International Net Sales		10,905	10,231
Net sales		40,430	40,490
Aerostar Lighter-than-air [Member]
Disaggregation of Revenue [Line Items]
Domestic Net Sales		6,548	6,206
International Net Sales		454	26
Aerostar Other [Member]
Disaggregation of Revenue [Line Items]
Domestic Net Sales		3,899	3,332
International Net Sales		0	42
Aerostar [Member]
Disaggregation of Revenue [Line Items]
Net sales		10,901	9,606
Intersegment Eliminations [Member]
Disaggregation of Revenue [Line Items]
Domestic Net Sales	[1]	(194)	(116)
Net sales	[1],[2]	(194)	(116)
All Segments [Member]
Disaggregation of Revenue [Line Items]
Net sales		$ 111,129	$ 93,535

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

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