Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2025	Oct. 31, 2024	Oct. 31, 2025	Oct. 31, 2024	Apr. 30, 2025
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 660,310		$ 660,310		$ 649,612
Less accumulated depreciation and amortization	(421,340)		(421,340)		(404,623)
Property, plant and equipment, net	238,970		238,970		244,989
Amortization and depreciation expense on property, plant and equipment	12,900	$ 11,900	25,500	$ 23,100
Finance lease, right-of-use asset, accumulated amortization	30,300		30,300		31,500
Land
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	4,369		4,369		4,264
Buildings and improvements
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	134,475		134,475		133,251
Buildings and improvements - finance leases
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	11,164		11,164		11,164
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	423,999		423,999		410,287
Machinery and equipment - finance leases
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	30,434		30,434		32,434
Software
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	34,539		34,539		34,107
Construction in progress
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 21,330		$ 21,330		$ 24,105