Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Jul. 31, 2025	Jul. 31, 2024
Schedule of Earnings Per Share, Two Class Method [Line Items]
Net income (loss)	$ (43.9)	$ 185.0
Net income (loss) per common share (in dollars per share)	$ (0.41)	$ 1.74
Net income (loss) per common share – assuming dilution	$ (0.41)	$ 1.74
Two-class method
Schedule of Earnings Per Share, Two Class Method [Line Items]
Net income (loss)	$ (43.9)	$ 185.0
Less: Net income (loss) allocated to participating securities	0.0	0.0
Net income (loss) allocated to common stockholders	$ (43.9)	$ 185.0
Weighted-average common shares outstanding	106.6	106.3
Add: Dilutive effect of stock options (in shares)	0.0	0.0
Weighted-average common shares outstanding – assuming dilution (in shares)	106.6	106.3
Net income (loss) per common share (in dollars per share)	$ (0.41)	$ 1.74
Net income (loss) per common share – assuming dilution	$ (0.41)	$ 1.74