Net Earnings Per Share - Calculations of Net Earnings Per Share - Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net earnings available to common shareholders	$ 5.6	$ 39.7
Weighted-average common shares outstanding (in millions)
Weighted-average common shares outstanding - basic	46.8	48.3
Weighted-average common shares outstanding - diluted	47.3	48.9
Net earnings per share - basic	$ 0.12	$ 0.82
Net earnings per share - diluted	$ 0.12	$ 0.81
Employee Stock Option
Weighted-average common shares outstanding (in millions)
Effect of dilutive securities	0.5	0.6