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, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	$ 356,984	$ 338,593
Available-for-sale, Gross Unrealized Gains	2,126	1,002
Available-for-sale, Gross Unrealized Losses	(14,022)	(18,474)
Fixed maturity securities-available-for-sale	345,088	321,121
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	159,914	166,019
Available-for-sale, Gross Unrealized Gains	904	463
Available-for-sale, Gross Unrealized Losses	(7,384)	(9,826)
Fixed maturity securities-available-for-sale	153,434	156,656
Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	175,574	150,915
Available-for-sale, Gross Unrealized Gains	1,200	530
Available-for-sale, Gross Unrealized Losses	(4,960)	(6,657)
Fixed maturity securities-available-for-sale	171,814	144,788
U.S. Agency-Based Mortgage-Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	5,803	5,984
Available-for-sale, Gross Unrealized Losses	(468)	(538)
Fixed maturity securities-available-for-sale	5,335	5,446
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	15,693	15,675
Available-for-sale, Gross Unrealized Gains	22	9
Available-for-sale, Gross Unrealized Losses	(1,210)	(1,453)
Fixed maturity securities-available-for-sale	$ 14,505	$ 14,231

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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