Investments - Investment Income (Loss) Summarized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule Of Investments [Line Items]
Recognized investment income (loss)	$ 661	$ 3,963	$ 4,947
Real estate investments	10,207	16,126	4,086
Net investment income	46,234	32,447	12,335
Gain (Loss) Related to Litigation Settlement			2,790
Available-for-Sale-Fixed-Maturity Securities [Member]
Schedule Of Investments [Line Items]
Investment income	17,626	6,367	1,375
Equity Securities [Member]
Schedule Of Investments [Line Items]
Investment income	1,551	1,204	1,411
Limited Partnership Investment [Member]
Schedule Of Investments [Line Items]
Recognized investment income (loss)	661	3,963	4,947
Cash and Cash Equivalents [Member]
Schedule Of Investments [Line Items]
Investment income	16,746	4,783	641
Investment Expense [Member]
Schedule Of Investments [Line Items]
Investment expense	(557)	(491)	(542)
Income (Loss) from Unconsolidated Joint Venture [Member]
Schedule Of Investments [Line Items]
Investment income	$ 0	$ 495	$ 417