Quarterly Results for 2023 and 2022 (Unaudited) - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Direct premiums written, period increase (decrease)	$ 16,500
Direct premiums written, period increase (decrease) (percent)	4.00%
Direct premiums written	$ 432,600		$ 1,921,833	$ 1,845,786	$ 1,671,252
Policies in force, period increase (decrease)	$ 2,379		$ (38,924)
Policies in force, increase (decrease) (percent)	0.30%		(4.60%)
Expense ratio, period increase (decrease) (percent)		25.10%		25.10%
Minimum
Revenues from External Customers and Long-Lived Assets [Line Items]
Expense ratio, period increase (decrease) (percent)	21.80%		21.80%
FLORIDA
Revenues from External Customers and Long-Lived Assets [Line Items]
Direct premiums written, period increase (decrease)	$ 2,000
Direct premiums written, period increase (decrease) (percent)	0.60%
States Other than Florida
Revenues from External Customers and Long-Lived Assets [Line Items]
Direct premiums written, period increase (decrease)		$ 14,600
Direct premiums written, period increase (decrease) (percent)		18.60%