Earnings Per Common Share - Dilutive Effect of Share-Based Awards (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Basic weighted-average common shares outstanding (in shares)	46.5	46.0
Diluted weighted-average shares outstanding (in shares)	47.2	46.0
Diluted earnings attributable to common shareholders	$ 24.3	$ 40.3
Diluted earnings per common share (in usd per share)	$ 0.51	$ 0.88
Dilutive effect of stock options and equivalents
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive effect of stock options and equivalents (in shares)	0.7	0.0