Note 7 - Goodwill and Core Deposit Intangibles - Changes in the Net Carrying Amount of Core Deposit Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Balance, beginning of period	$ 1,057
Balance, end of period	2,285	$ 1,057
Core Deposits [Member]
Balance, beginning of period	1,057	1,225	$ 1,405
Finite-lived Intangible Assets Acquired	1,519	0	0
Amortized to expense	(291)	(168)	(180)
Balance, end of period	$ 2,285	$ 1,057	$ 1,225