Note 4 - Qualified Affordable Housing Project Investment (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Amortization Method Qualified Affordable Housing Project Investments, Amortization	$ 89,000	$ 89,000
Affordable Housing Tax Credits and Other Tax Benefits, Amount	105,000	$ 106,000
Other Assets [Member]
Investments, Total	2,400,000		$ 2,500,000
Other Liabilities [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	$ 216,000		$ 216,000