Earnings per Common Share - Schedule of Calculations of Basic and Diluted Earnings (Loss) per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Earnings Per Share [Abstract]
Net income	$ 84.8	$ 43.9
Dividends allocated to participating securities	(0.1)	(0.1)
Earnings available for common stockholders used in calculation of basic earnings per common share	$ 84.7	$ 43.8
Weighted average number of common shares outstanding, basic (in shares)	50.1	49.2
Basic earnings per common share (in dollars per share)	$ 1.69	$ 0.89
Dividends allocated to participating securities	$ (0.1)	$ (0.1)
Earnings available for common stockholders used in calculation of diluted earnings per common share	$ 84.7	$ 43.8
Effect of shares issuable under share-based compensation plans (in shares)	0.6	0.7
Weighted average number of common shares outstanding, diluted (in shares)	50.7	49.9
Diluted earnings per common share (in dollars per share)	$ 1.67	$ 0.88