Note 5 - Goodwill and Intangible Assets - Changes in the Net Carrying Amount of Core Deposit Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Balance at beginning of period	$ 2,285
Balance at end of period	2,203
Core Deposits [Member]
Balance at beginning of period	2,285	$ 1,057
Core deposit intangible acquired	0	0
Amortization	(82)	(42)
Balance at end of period	$ 2,203	$ 1,015