Note 15 - Off Balance Sheet Risks, Commitments, and Contingent Liabilities - Contractual Amounts of Financial Instruments With Off Balance Sheet Risk (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Fixed Rate [Member] | Commitments to Make Loans [Member]
Financial Instrument off Balance Sheet Risk, Amount	$ 12,403	$ 11,577
Fixed Rate [Member] | Unused lines of Credit [Member]
Financial Instrument off Balance Sheet Risk, Amount	8,684	7,916
Fixed Rate [Member] | Standby Letters of Credit [Member]
Financial Instrument off Balance Sheet Risk, Amount	531	531
Variable Rate [Member] | Commitments to Make Loans [Member]
Financial Instrument off Balance Sheet Risk, Amount	26,290	20,415
Variable Rate [Member] | Unused lines of Credit [Member]
Financial Instrument off Balance Sheet Risk, Amount	96,982	111,230
Variable Rate [Member] | Standby Letters of Credit [Member]
Financial Instrument off Balance Sheet Risk, Amount	$ 1,336	$ 3,164