Restructuring - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2021	Jul. 31, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring charges, net	$ 313	$ 3,460
Manufacturing Plant Closure
Restructuring Cost and Reserve [Line Items]
Restructuring charges, net	300	$ 1,800
Facility Closing | Discontinued Operations, Disposed of by Sale | Humboldt Facility
Restructuring Cost and Reserve [Line Items]
Gain (Loss) on Disposition of Business	2,300
Employee Severance | Nationwide Reductions In Force
Restructuring Cost and Reserve [Line Items]
Restructuring charges, net	$ 1,700