Note 11 - Fair Values - Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - Fair Value, Nonrecurring [Member] - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Impaired loans	$ 2,425,000	$ 2,880,000
Foreclosed assets	374,000	701,000
Total	2,799,000	3,581,000
Fair Value, Inputs, Level 1 [Member]
Impaired loans	0	0
Foreclosed assets	0	0
Total	0	0
Fair Value, Inputs, Level 2 [Member]
Impaired loans	0	0
Foreclosed assets	0	0
Total	0	0
Fair Value, Inputs, Level 3 [Member]
Impaired loans	2,425,000	2,880,000
Foreclosed assets	374,000	701,000
Total	$ 2,799,000	$ 3,581,000