Earnings Per Common Share - Computation of Basic and Diluted Earnings Per Common Share Attributable to Controlling Interest (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Nov. 30, 2024	Nov. 30, 2023	Nov. 30, 2024	Nov. 30, 2023
Numerator (basic & diluted):
Net earnings (loss) attributable to controlling interest - income (loss) available to common shareholders		$ 12.8	$ (6.0)	$ 41.2	$ 52.5
Denominator:
Basic earnings (loss) per common share attributable to controlling interest - weighted average common shares	[1]	49.5	49.3	49.4	49.3
Effect of dilutive securities		1.1	0.0	1.1	0.0
Diluted earnings (loss) per common share attributable to controlling interest - adjusted weighted average common shares	[2]	50.6	49.3	50.5	49.3
Basic earnings (loss) per common share attributable to controlling interest		$ 0.26	$ (0.12)	$ 0.83	$ 1.07
Diluted earnings (loss) per common share attributable to controlling interest		$ 0.25	$ (0.12)	$ 0.82	$ 1.07
Anti-dilutive non-qualified stock options and restricted common share awards	[3]	0.1	0.0	0.2	0.0

[1] Prior to the third quarter of fiscal 2024, reported Weighted average common shares outstanding (Basic) and Common shares outstanding at end of period reflect the basic common shares at the Separation. This share amount is being utilized for the calculation of basic earnings per common share for periods presented prior to the Separation.

[2] Prior to the third quarter of fiscal 2024, reported Weighted average common shares outstanding (Diluted) reflects the basic common shares at the Separation. This share amount is being utilized for the calculation of diluted earnings per common share for periods presented prior to the Separation.

[3] These non-qualified stock options and restricted common share awards were excluded from the calculation of diluted earnings per common share because their inclusion would have been anti-dilutive.