Treasury Stock - Schedule of repurchase of common stock (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended	15 Months Ended
	Feb. 28, 2025	Nov. 30, 2024	Aug. 31, 2024	Feb. 29, 2024	Nov. 30, 2023	Aug. 31, 2023	Feb. 28, 2025	Feb. 28, 2025	Mar. 20, 2024	Dec. 13, 2023
Equity, Class of Treasury Stock [Line Items]
Authorized amount of stock to be repurchased	$ 120.8						$ 120.8	$ 120.8
Less repurchases made under these authorizations	(30.6)	$ (5.0)	$ (5.0)	$ (54.2)	$ (52.3)	$ (36.2)	(40.6)
Remaining Board authorization at February 28, 2025	$ 46.6						$ 46.6	46.6
Board Authorized 2023 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Authorized amount of stock to be repurchased										$ 66.2
Board Authorized 2024 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Authorized amount of stock to be repurchased									$ 54.6
Under all Board Authorizations
Equity, Class of Treasury Stock [Line Items]
Less repurchases made under these authorizations								$ (74.2)