Income Taxes - Schedule of Company's Deferred Income Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred income tax assets:
Discounting of net unpaid loss and loss adjustment expenses	$ 15,035	$ 16,164
Unearned premiums	6,072	6,173
Accrued expenses and other	2,103	2,403
State income tax	2,495	2,468
Accrued policyholder dividends	1,723	1,841
Accrued insurance-related assessments	1,870	1,990
Net unrealized loss on securities		1,182
Total deferred tax assets	29,298	32,221
Deferred income tax liabilities:
Deferred policy acquisition costs	(4,578)	(4,391)
Net unrealized gain on securities available-for-sale	(839)
Property and equipment and other	(365)	(473)
Salvage and subrogation	(284)	(320)
Loss reserves adjustment	(2,829)	(4,243)
Total deferred income tax liabilities	(8,895)	(9,427)
Net deferred income taxes	$ 20,403	$ 22,794