Revenue Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Disaggregation of Revenue [Line Items]
Net sales	$ 96,607	$ 100,533	$ 268,282	$ 296,769
Applied Technology [Member]
Disaggregation of Revenue [Line Items]
Net sales	34,838	28,500	112,347	97,596
Aerostar [Member]
Disaggregation of Revenue [Line Items]
Net sales	18,010	15,661	42,626	41,040
Engineered Films [Member]
Disaggregation of Revenue [Line Items]
Net sales	43,765	56,406	113,415	158,214
All Segments [Member]
Disaggregation of Revenue [Line Items]
Net sales	96,607	100,533	268,282	296,769
UNITED STATES | Lighter-than-air [Member]
Disaggregation of Revenue [Line Items]
Net sales	14,849	11,071	30,939	26,230
UNITED STATES | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales	40,460	54,640	103,396	151,198
UNITED STATES | Precision Agriculture [Member]
Disaggregation of Revenue [Line Items]
Net sales	27,599	22,956	86,458	72,914
UNITED STATES | Other Product [Member]
Disaggregation of Revenue [Line Items]
Net sales	3,158	4,577	11,633	14,665
UNITED STATES | Applied Technology [Member] | Precision Agriculture [Member]
Disaggregation of Revenue [Line Items]
Net sales	27,599	22,957	86,460	72,915
UNITED STATES | Aerostar [Member] | Lighter-than-air [Member]
Disaggregation of Revenue [Line Items]
Net sales	14,849	11,071	30,939	26,230
UNITED STATES | Aerostar [Member] | Other Product [Member]
Disaggregation of Revenue [Line Items]
Net sales	3,158	4,577	11,633	14,665
UNITED STATES | Engineered Films [Member] | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales	40,466	54,673	103,500	151,278
Non-US [Member] | Lighter-than-air [Member]
Disaggregation of Revenue [Line Items]
Net sales	2	0	48	49
Non-US [Member] | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales	3,299	1,733	9,915	6,936
Non-US [Member] | Precision Agriculture [Member]
Disaggregation of Revenue [Line Items]
Net sales	7,239	5,543	25,887	24,681
Non-US [Member] | Other Product [Member]
Disaggregation of Revenue [Line Items]
Net sales	1	13	6	96
Non-US [Member] | Applied Technology [Member] | Precision Agriculture [Member]
Disaggregation of Revenue [Line Items]
Net sales	7,239	5,543	25,887	24,681
Non-US [Member] | Aerostar [Member] | Lighter-than-air [Member]
Disaggregation of Revenue [Line Items]
Net sales	2	0	48	49
Non-US [Member] | Aerostar [Member] | Other Product [Member]
Disaggregation of Revenue [Line Items]
Net sales	1	13	6	96
Non-US [Member] | Engineered Films [Member] | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales	3,299	1,733	9,915	6,936
Consolidation, Eliminations [Member]
Disaggregation of Revenue [Line Items]
Net sales	(6)	(34)	(106)	(81)
Consolidation, Eliminations [Member] | UNITED STATES | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales	(6)	(33)	(104)	(80)
Consolidation, Eliminations [Member] | UNITED STATES | Precision Agriculture [Member]
Disaggregation of Revenue [Line Items]
Net sales	0	(1)	(2)	(1)
Consolidation, Eliminations [Member] | Non-US [Member] | Plastic Films and Sheeting [Member]
Disaggregation of Revenue [Line Items]
Net sales	$ 0	$ 0	$ 0	$ 0