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 ($)	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	$ 326,171,000	$ 338,593,000
Available-for-sale, Gross Unrealized Gains	2,688,000	1,002,000
Available-for-sale, Gross Unrealized Losses	(11,795,000)	(18,474,000)
Available-for-sale fixed maturity, Fair Value	317,064,000	321,121,000
Available-for-sale securities, credit allowance	0	0
Fixed maturity securities, available-for-sale, allowance for credit losses	0	0
States and Political Subdivisions [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	138,031,000	166,019,000
Available-for-sale, Gross Unrealized Gains	583,000	463,000
Available-for-sale, Gross Unrealized Losses	(6,719,000)	(9,826,000)
Available-for-sale fixed maturity, Fair Value	131,895,000	156,656,000
Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	168,134,000	150,915,000
Available-for-sale, Gross Unrealized Gains	2,105,000	530,000
Available-for-sale, Gross Unrealized Losses	(3,486,000)	(6,657,000)
Available-for-sale fixed maturity, Fair Value	166,753,000	144,788,000
U.S. Agency-Based Mortgage-Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale, Amortized Cost	5,190,000	5,984,000
Available-for-sale, Gross Unrealized Gains		0
Available-for-sale, Gross Unrealized Losses	(445,000)	(538,000)
Available-for-sale fixed maturity, Fair Value	4,745,000	5,446,000
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	14,816,000	15,675,000
Available-for-sale, Gross Unrealized Gains		9,000
Available-for-sale, Gross Unrealized Losses	(1,145,000)	(1,453,000)
Available-for-sale fixed maturity, Fair Value	$ 13,671,000	$ 14,231,000