Net Earnings Per Share (Reconciliation of Net Earnings Attributable to Common Shares Used in Basic and Diluted Net Earnings Per Share Calculation) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Earnings Per Share [Abstract]
Net earnings	$ 65.9	$ 60.2	$ 125.8	$ 107.5
(Earnings) allocated to participating vested share awards	0.0	0.0	0.0	(0.1)
(Earnings) allocated to participating vested share awards	0.0	0.0	0.0	(0.1)
Net earnings attributable to common shares	$ 65.9	$ 60.2	$ 125.8	$ 107.4