Note 4 - Repurchase Agreements - Risks With Individual Counterparties (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Amount at risk	$ 4,800	$ 6,000
Mirae Asset Securities (USA) Inc. [Member]
Amount at risk	$ 1,129	$ 1,564
Percent of Stockholders' Equity at Risk	13.50%	19.20%
Weighted Average Maturity (Year)	79 years	18 years
DV Securities, LLC Repo [Member]
Amount at risk	$ 1,129
Percent of Stockholders' Equity at Risk	13.50%
Weighted Average Maturity (Year)	29 years
Mitsubishi UFJ Securities, Inc [Member]
Amount at risk	$ 924	$ 1,128
Percent of Stockholders' Equity at Risk	11.10%	13.90%
Weighted Average Maturity (Year)	23 years	23 years
South Street Securities, LLC [Member]
Amount at risk	$ 844	$ 922
Percent of Stockholders' Equity at Risk	10.10%	11.30%
Weighted Average Maturity (Year)	51 years	52 years
Citigroup Global Markets Inc [Member]
Amount at risk		$ 1,302
Percent of Stockholders' Equity at Risk		16.00%
Weighted Average Maturity (Year)		26 years