Note 11 - Assets and Liabilities Measured and Reported at Fair Value - Assets Measured at Fair Value on a Non-recurring Basis (Details) - Fair Value, Nonrecurring [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Collateral dependent loans, fair value	$ 0
Other real estate owned, fair value	0	$ 281
Other real estate owned, gain (loss)	0	0
Impaired loans		7,546
Impaired loans		0
Fair Value, Inputs, Level 1 [Member]
Collateral dependent loans, fair value	0
Other real estate owned, fair value	0	0
Impaired loans		0
Fair Value, Inputs, Level 2 [Member]
Collateral dependent loans, fair value	7,571
Other real estate owned, fair value	281	0
Impaired loans		0
Fair Value, Inputs, Level 3 [Member]
Collateral dependent loans, fair value	7,571
Other real estate owned, fair value	$ 281	281
Impaired loans		$ 7,546