Earnings Per Share - Calculation of Pro Forma Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Numerator:
Net income attributable to common stock	$ 12.0	$ 23.8
Denominator:
Weighted-average shares of common stock outstanding—basic (in shares)	41,444,200	43,969,713
Potential shares of common stock:
Weighted average diluted common stock outstanding (in shares)	42,710,577	45,327,390
Basic
Basic earnings per share of common stock attributable to controlling interests (in dollars per share)	$ 0.29	$ 0.54
Diluted
Diluted earnings per share of common stock attributable to controlling interests (in dollars per share)	$ 0.28	$ 0.53
Restricted stock units
Potential shares of common stock:
Restricted stock units/Employee stock options (in shares)	7,539	10,112
Employee stock options
Potential shares of common stock:
Restricted stock units/Employee stock options (in shares)	1,258,838	1,347,565