Earnings per Share - Reconciliation of Numerator and Denominator of Basic and Diluted Earnings per Share Calculation and Anti-dilutive Share-based Awards (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Earnings Per Share Basic And Diluted [Line Items]
Basic	$ 0.54	$ 0.80
Diluted	$ 0.52	$ 0.77
Net earnings	$ 15.8	$ 26.4
Basic weighted average number of common shares outstanding	29.2	32.9
Dilutive awards	1.3	1.5
Diluted weighted average number of common shares outstanding	30.5	34.4