Note 11 - Assets and Liabilities Measured and Reported at Fair Value - Significant Unobservable Inputs (Details) - Appraisal Discount Method [Member] - Fair Value, Inputs, Level 3 [Member] - Impaired Loans [Member] $ in Thousands	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Collateral dependent loans, fair value	$ 7,571	$ 7,546
Other real estate owned, fair value	$ 281	$ 281
Weighted Average [Member]
Impaired Loans, Measurement Input	0.107	0.107
Other Real Estate Owned, Measurement Input	0.360	0.360