Note 4 - Goodwill and Core Deposit Intangibles - Changes in the Net Carrying Amount of Core Deposit Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Balance at beginning of period	$ 1,962
Balance at end of period	1,885
Core Deposits [Member]
Balance at beginning of period	1,962	$ 2,285
Core deposit intangible acquired	0	0
Amortization	(77)	(82)
Balance at end of period	$ 1,885	$ 2,203