Net Earnings Per Share (Reconciliation of Earnings (loss) to Earnings (loss) Attributable to Common Shares Used in Basic and Diluted (Loss) Earnings Per Share Calculation) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Earnings Per Share [Abstract]
Net earnings	$ 60.2	$ 52.2	$ 107.5	$ 96.6
Earnings allocated to participating vested share awards	0.0	(0.1)	(0.1)	(0.2)
Earnings from continuing operations attributable to common shares	$ 60.2	$ 52.1	$ 107.4	$ 96.4