Earnings Per Share (Details 1) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended				6 Months Ended
	Oct. 31, 2025	Jul. 31, 2025	Oct. 31, 2024	Jul. 31, 2024	Oct. 31, 2025	Oct. 31, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net income (loss)	$ 241.3	$ (43.9)	$ (24.5)	$ 185.0	$ 197.4	$ 160.5
Net income (loss) per common share – assuming dilution	$ 2.26		$ (0.23)		$ 1.85	$ 1.51
Treasury Stock Method [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net income (loss)	$ 241.3		$ (24.5)		$ 197.4	$ 160.5
Weighted-average common shares outstanding	106.7		106.4		106.6	106.4
Weighted-average common shares outstanding – assuming dilution (in shares)	106.9		106.7		106.9	106.6
Net income (loss) per common share – assuming dilution	$ 2.26		$ (0.23)		$ 1.85	$ 1.51
Employee stock options | Treasury Stock Method [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dilutive effect (in shares)	0.0		0.0		0.0	0.0
Restricted shares, restricted stock units, and performance units | Treasury Stock Method [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dilutive effect (in shares)	0.2		0.3		0.3	0.2