Investments - Gross Unrealized Gains and Losses and Cost or Amortized Cost, Allowance for Credit Losses and Fair Value of Investments Classified as Available-for-Sale (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	$ 316,286	$ 318,975
Available-for-sale, Gross Unrealized Gains	2,300	1,396
Available-for-sale, Gross Unrealized Losses	(11,871)	(12,621)
Fixed maturity securities-available-for-sale	306,715	307,750
Debt Securities Available For Sale Allowance For Credit Loss	0	0
States and Political Subdivisions [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	165,127	156,488
Available-for-sale, Gross Unrealized Gains	164	148
Available-for-sale, Gross Unrealized Losses	(9,592)	(8,430)
Fixed maturity securities-available-for-sale	155,699	148,206
Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	131,993	143,070
Available-for-sale, Gross Unrealized Gains	2,136	1,248
Available-for-sale, Gross Unrealized Losses	(1,276)	(2,783)
Fixed maturity securities-available-for-sale	132,853	141,535
U.S. Agency-Based Mortgage-Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	4,265	4,545
Available-for-sale, Gross Unrealized Losses	(377)	(486)
Fixed maturity securities-available-for-sale	3,888	4,059
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	14,901	14,872
Available-for-sale, Gross Unrealized Losses	(626)	(922)
Fixed maturity securities-available-for-sale	$ 14,275	$ 13,950