Note 4 - Goodwill and Core Deposit Intangibles - Carrying Value of Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Balance at beginning of period	$ 12,513	$ 12,513	$ 12,513
Goodwill acquired	0	0
Recast adjustments	0	0
Impairment	0	0	0
Balance at end of period	$ 12,513	$ 12,513	$ 12,513