Revenue Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
Disaggregation of Revenue [Line Items]
Net sales	$ 86,496	$ 98,178
Applied Technology [Member]
Disaggregation of Revenue [Line Items]
Net sales	42,007	41,725
Aerostar [Member]
Disaggregation of Revenue [Line Items]
Net sales	11,151	12,190
Engineered Films [Member]
Disaggregation of Revenue [Line Items]
Net sales	33,398	44,292
All Segments [Member]
Disaggregation of Revenue [Line Items]
Net sales	86,496	98,178
UNITED STATES | Lighter-than-air [Member]
Disaggregation of Revenue [Line Items]
Net sales	6,082	7,029
UNITED STATES | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales	30,496	41,733
UNITED STATES | Precision Agriculture [Member]
Disaggregation of Revenue [Line Items]
Net sales	30,861	29,584
UNITED STATES | Other Product [Member]
Disaggregation of Revenue [Line Items]
Net sales	5,052	5,122
UNITED STATES | Applied Technology [Member] | Precision Agriculture [Member]
Disaggregation of Revenue [Line Items]
Net sales	30,861	29,584
UNITED STATES | Aerostar [Member] | Lighter-than-air [Member]
Disaggregation of Revenue [Line Items]
Net sales	6,082	7,029
UNITED STATES | Aerostar [Member] | Other Product [Member]
Disaggregation of Revenue [Line Items]
Net sales	5,052	5,122
UNITED STATES | Engineered Films [Member] | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales	30,556	41,762
Non-US [Member] | Lighter-than-air [Member]
Disaggregation of Revenue [Line Items]
Net sales	12	34
Non-US [Member] | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales	2,842	2,530
Non-US [Member] | Precision Agriculture [Member]
Disaggregation of Revenue [Line Items]
Net sales	11,146	12,141
Non-US [Member] | Other Product [Member]
Disaggregation of Revenue [Line Items]
Net sales	5	5
Non-US [Member] | Applied Technology [Member] | Precision Agriculture [Member]
Disaggregation of Revenue [Line Items]
Net sales	11,146	12,141
Non-US [Member] | Aerostar [Member] | Lighter-than-air [Member]
Disaggregation of Revenue [Line Items]
Net sales	12	34
Non-US [Member] | Aerostar [Member] | Other Product [Member]
Disaggregation of Revenue [Line Items]
Net sales	5	5
Non-US [Member] | Engineered Films [Member] | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales	2,842	2,530
Consolidation, Eliminations [Member]
Disaggregation of Revenue [Line Items]
Net sales	(60)	(29)
Consolidation, Eliminations [Member] | UNITED STATES | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales	(60)	(29)
Consolidation, Eliminations [Member] | UNITED STATES | Precision Agriculture [Member]
Disaggregation of Revenue [Line Items]
Net sales	0	0
Consolidation, Eliminations [Member] | Non-US [Member] | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales	$ 0	$ 0