Long-term Debt - Schedule of Maybrooke Junior Subordinated Debentures (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Principal	$ 143.8	$ 143.8
Subordinated debentures
Debt Instrument [Line Items]
Interest rate	7.92%	3.35%
Principal	$ 91.8	$ 91.8
Carrying Value	$ 85.9	$ 85.5
London Interbank Offered Rate (LIBOR) | Subordinated debentures
Debt Instrument [Line Items]
Interest rate basis spread	3.15%	3.15%