Note 15 - Disclosures About Fair Value of Assets and Liabilities - Fair Value Quantitative Information (Details) - Fair Value, Inputs, Level 3 [Member] - Valuation, Market Approach [Member] $ in Thousands	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Impaired loans (collateral dependent)	$ 1,483	$ 10,428
Foreclosed assets held for sale	$ 233	$ 909
Minimum [Member]
Impaired loans (collateral dependent)	0	0
Foreclosed assets held for sale	0.3	0.25
Maximum [Member]
Impaired loans (collateral dependent)	1	1
Foreclosed assets held for sale	0.3	0.34
Weighted Average [Member]
Impaired loans (collateral dependent)	0.22	0.08
Foreclosed assets held for sale	0.3	0.3