Note 4 - Investments - Net Investment Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Investment income	$ 1,765	$ 1,136
Cash and Cash Equivalents [Member]
Investment income	266	39
Fixed Income Securities [Member]
Investment income	194	72
Series B Cumulative Convertible Preferred Stock [Member] | HC Government Realty Trust, Inc [Member]
Dividends on investment in HC Series B Stock	1,025	1,025
Partnership [Member]
Investment income	$ 280	$ 0