Note 3 - Mortgage-backed Securities - Net Gain (Loss) From Sale of MBS (Details) - Collateralized Mortgage-Backed Securities [Member] - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Proceeds from sales of MBS	$ 18,175,322	$ 23,096,853
Carrying value of MBS sold	18,195,000	23,955,000
Net loss on sales of MBS	(20,000)	(858,000)
Gross gain sales of MBS	0	0
Gross loss on sales of MBS	$ (20,000)	$ (858,000)