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	Mar. 31, 2025	Dec. 31, 2024
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	$ 323,931	$ 318,975
Available-for-sale, Gross Unrealized Gains	1,974	1,396
Available-for-sale, Gross Unrealized Losses	(11,179)	(12,621)
Fixed maturity securities-available-for-sale	314,726	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	163,615	156,488
Available-for-sale, Gross Unrealized Gains	208	148
Available-for-sale, Gross Unrealized Losses	(8,157)	(8,430)
Fixed maturity securities-available-for-sale	155,666	148,206
Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	141,024	143,070
Available-for-sale, Gross Unrealized Gains	1,766	1,248
Available-for-sale, Gross Unrealized Losses	(1,880)	(2,783)
Fixed maturity securities-available-for-sale	140,910	141,535
U.S. Agency-Based Mortgage-Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	4,406	4,545
Available-for-sale, Gross Unrealized Losses	(403)	(486)
Fixed maturity securities-available-for-sale	4,003	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	14,886	14,872
Available-for-sale, Gross Unrealized Losses	(739)	(922)
Fixed maturity securities-available-for-sale	$ 14,147	$ 13,950