Capital Stock and Stock-Based Awards - Schedule of Intrinsic value of stock options exercised, pretax stock-based compensation cost and related tax benefits (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	May 31, 2024	May 31, 2023	May 31, 2022
Share-Based Payment Arrangement [Abstract]
Total intrinsic value of stock options exercised	$ 6.4	$ 8.2	$ 5.1
Total stock-based compensation cost (pretax)	11.0	10.5	7.8
Tax benefits (shortfalls) related to stock-based compensation cost	$ 5.0	$ (7.8)	$ 2.3
Weighted average grant date fair value per option (in Dollars per share)	$ 11.53	$ 11.62	$ 8.04