Revenue Disaggregation of Revenue (Details) - USD ($) $ in Thousands		3 Months Ended
		Apr. 30, 2019	Apr. 30, 2018
Disaggregation of Revenue [Line Items]
Net sales		$ 98,178	$ 111,129
Applied Technology [Member]
Disaggregation of Revenue [Line Items]
Net sales		41,725	40,430
Aerostar [Member]
Disaggregation of Revenue [Line Items]
Net sales		12,190	10,901
Engineered Films [Member]
Disaggregation of Revenue [Line Items]
Net sales	[1]	44,292	59,992
All Segments [Member]
Disaggregation of Revenue [Line Items]
Net sales		98,178	111,129
UNITED STATES | Lighter-than-air [Member]
Disaggregation of Revenue [Line Items]
Net sales		7,029	6,548
UNITED STATES | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales		41,733	55,103
UNITED STATES | Precision Agriculture [Member]
Disaggregation of Revenue [Line Items]
Net sales		29,584	29,525
UNITED STATES | Other Product [Member]
Disaggregation of Revenue [Line Items]
Net sales		5,122	3,899
UNITED STATES | Applied Technology [Member] | Precision Agriculture [Member]
Disaggregation of Revenue [Line Items]
Net sales		29,584	29,525
UNITED STATES | Aerostar [Member] | Lighter-than-air [Member]
Disaggregation of Revenue [Line Items]
Net sales		7,029	6,548
UNITED STATES | Aerostar [Member] | Other Product [Member]
Disaggregation of Revenue [Line Items]
Net sales		5,122	3,899
UNITED STATES | Engineered Films [Member] | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales		41,762	55,297
Non-US [Member] | Lighter-than-air [Member]
Disaggregation of Revenue [Line Items]
Net sales		34	454
Non-US [Member] | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales		2,530	4,695
Non-US [Member] | Precision Agriculture [Member]
Disaggregation of Revenue [Line Items]
Net sales		12,141	10,905
Non-US [Member] | Other Product [Member]
Disaggregation of Revenue [Line Items]
Net sales		5	0
Non-US [Member] | Applied Technology [Member] | Precision Agriculture [Member]
Disaggregation of Revenue [Line Items]
Net sales		12,141	10,905
Non-US [Member] | Aerostar [Member] | Lighter-than-air [Member]
Disaggregation of Revenue [Line Items]
Net sales		34	454
Non-US [Member] | Aerostar [Member] | Other Product [Member]
Disaggregation of Revenue [Line Items]
Net sales		5	0
Non-US [Member] | Engineered Films [Member] | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales		2,530	4,695
Consolidation, Eliminations [Member]
Disaggregation of Revenue [Line Items]
Net sales	[2]	(29)	(194)
Consolidation, Eliminations [Member] | UNITED STATES | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales		(29)	(194)
Consolidation, Eliminations [Member] | Non-US [Member] | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales		$ 0	$ 0

[1] Hurricane recovery film sales for the three-month period ended April 30, 2019 and 2018, were $17 and $8,919, respectively.

[2] Intersegment sales for both fiscal 2020 and 2019 were primarily sales from Engineered Films to Aerostar.