Long-term Debt - Schedule of Maybrooke Junior Subordinated Debentures (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Nov. 16, 2023
Debt Instrument [Line Items]
Principal	$ 143.8	$ 143.8
Subordinated debentures
Debt Instrument [Line Items]
Interest rate basis spread	3.15%	3.15%
Interest rate	7.77%	8.79%
Principal	$ 91.8	$ 91.8	$ 91.8
Carrying Value	$ 81.2	$ 80.4	$ 81.2