Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2025	Jan. 31, 2024	Jan. 31, 2025	Jan. 31, 2024	Apr. 30, 2024
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 659,948		$ 659,948		$ 653,724
Less accumulated amortization and depreciation	(410,288)		(410,288)		(381,263)
Property, plant and equipment, net	249,660		249,660		272,461
Amortization and depreciation expense on property, plant and equipment	12,900	$ 10,600	36,800	$ 30,000
Finance lease, right-of-use asset, accumulated amortization	31,800		31,800		31,700
Land
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	4,475		4,475		4,475
Buildings and improvements
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	138,309		138,309		131,663
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	413,148		413,148		370,940
Machinery and equipment - finance leases
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	33,244		33,244		32,173
Software
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	34,005		34,005		39,252
Construction in progress
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 25,603		$ 25,603		$ 64,057