Revenue Disaggregation of Revenues (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 31, 2020 USD ($)	Oct. 31, 2019 USD ($)	Jul. 31, 2019 USD ($)	Apr. 30, 2019 USD ($)	Jan. 31, 2019 USD ($)	Oct. 31, 2018 USD ($)	Jul. 31, 2018 USD ($)	Apr. 30, 2018 USD ($)	Jan. 31, 2020 segment	Jan. 31, 2020 ReportingUnits	Jan. 31, 2020 USD ($)	Jan. 31, 2019 segment	Jan. 31, 2019 ReportingUnits	Jan. 31, 2019 USD ($)	Jan. 31, 2018 segment	Jan. 31, 2018 ReportingUnits	Jan. 31, 2018 USD ($)
Disaggregation of Revenue [Line Items]
Number of reportable segments									3	3		3	3		3	3
Net sales	$ 85,761	$ 100,533	$ 98,058	$ 98,178	$ 88,022	$ 104,833	$ 102,684	$ 111,129			$ 382,530			$ 406,668			$ 377,317
ELIM
Disaggregation of Revenue [Line Items]
Net sales											(92)			(522)			(584)
ATD
Disaggregation of Revenue [Line Items]
Net sales											130,460			129,749			124,688
EFD
Disaggregation of Revenue [Line Items]
Net sales											197,719			226,574			213,298
AERO
Disaggregation of Revenue [Line Items]
Net sales											54,443			50,867			39,915
All Segments
Disaggregation of Revenue [Line Items]
Net sales											382,530			406,668			377,317
Domestic
Disaggregation of Revenue [Line Items]
Net sales											340,398			358,339			335,761
Lighter-than-Air | Domestic
Disaggregation of Revenue [Line Items]
Net sales											36,535			37,866			24,956
Lighter-than-Air | Domestic | AERO
Disaggregation of Revenue [Line Items]
Net sales											36,535			37,866			24,956
Lighter-than-Air | International
Disaggregation of Revenue [Line Items]
Net sales											52			932			93
Lighter-than-Air | International | AERO
Disaggregation of Revenue [Line Items]
Net sales											52			932			93
Plastic Films & Sheeting | Domestic
Disaggregation of Revenue [Line Items]
Net sales											186,997			208,370			200,746
Plastic Films & Sheeting | Domestic | ELIM
Disaggregation of Revenue [Line Items]
Net sales											(90)			(512)			(584)
Plastic Films & Sheeting | Domestic | EFD
Disaggregation of Revenue [Line Items]
Net sales											187,087			208,882			201,330
Plastic Films & Sheeting | International
Disaggregation of Revenue [Line Items]
Net sales											10,632			17,692			11,968
Plastic Films & Sheeting | International | EFD
Disaggregation of Revenue [Line Items]
Net sales											10,632			17,692			11,968
Precision Agriculture Equipment | Domestic
Disaggregation of Revenue [Line Items]
Net sales											99,135			100,041			95,249
Precision Agriculture Equipment | Domestic | ELIM
Disaggregation of Revenue [Line Items]
Net sales											(2)			(10)			0
Precision Agriculture Equipment | Domestic | ATD
Disaggregation of Revenue [Line Items]
Net sales											99,137			100,051			95,249
Precision Agriculture Equipment | International
Disaggregation of Revenue [Line Items]
Net sales											31,323			29,698			29,439
Precision Agriculture Equipment | International | ATD
Disaggregation of Revenue [Line Items]
Net sales											31,323			29,698			29,439
Other | Domestic
Disaggregation of Revenue [Line Items]
Net sales											17,731			12,062			14,810
Other | Domestic | AERO
Disaggregation of Revenue [Line Items]
Net sales											17,731			12,062			14,810
Other | International
Disaggregation of Revenue [Line Items]
Net sales											125			7			56
Other | International | AERO
Disaggregation of Revenue [Line Items]
Net sales											$ 125			$ 7			$ 56