Note 13 - Disclosures About Fair Value of Assets and Liabilities - Fair Value of Assets Measured on Non-recurring Basis (Details) - Fair Value, Nonrecurring [Member] - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Impaired loans, fair value	$ 1,418	$ 5,809
Foreclosed assets held for sale, fair value	0	371
Fair Value, Inputs, Level 1 [Member]
Impaired loans, fair value	0	0
Foreclosed assets held for sale, fair value	0	0
Fair Value, Inputs, Level 2 [Member]
Impaired loans, fair value	0	0
Foreclosed assets held for sale, fair value	0	0
Fair Value, Inputs, Level 3 [Member]
Impaired loans, fair value	1,418	5,809
Foreclosed assets held for sale, fair value	$ 0	$ 371