Investments in Securities and Fair Value Investments in Securities (Schedule of Fair Value Assets Measured on Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, available-for-sale, at fair value	$ 63,847	$ 53,989
Equity securities, at fair value (cost: December 31, 2023: $22,981; December 31, 2022: $25,278)	37,212	51,691
Money market funds and U.S. Treasury bills	110,224	103,649
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, available-for-sale, at fair value	2,220	4,322
Equity securities, at fair value (cost: December 31, 2023: $22,981; December 31, 2022: $25,278)	37,212	51,691
Money market funds and U.S. Treasury bills	110,224	103,649
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, available-for-sale, at fair value	61,627	49,667
Equity securities, at fair value (cost: December 31, 2023: $22,981; December 31, 2022: $25,278)	0	0
Money market funds and U.S. Treasury bills	0	0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, available-for-sale, at fair value	0	0
Equity securities, at fair value (cost: December 31, 2023: $22,981; December 31, 2022: $25,278)	0	0
Money market funds and U.S. Treasury bills	0	0
General obligations of U.S. states, territories and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, available-for-sale, at fair value	36,666	42,878
General obligations of U.S. states, territories and political subdivisions | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, available-for-sale, at fair value	2,220	4,322
General obligations of U.S. states, territories and political subdivisions | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, available-for-sale, at fair value	34,446	38,556
General obligations of U.S. states, territories and political subdivisions | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, available-for-sale, at fair value	0	0
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, available-for-sale, at fair value	27,181	11,111
Corporate debt securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, available-for-sale, at fair value	0	0
Corporate debt securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, available-for-sale, at fair value	27,181	11,111
Corporate debt securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, available-for-sale, at fair value	$ 0	$ 0