Note 10 - Stock-based Compensation - Shares Grant to Board Directors (Details) - Corporate and Bank Board Directors [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Shares Granted (in shares)	11,529	11,166	10,489	17,716
Total Cost	$ 350	$ 359	$ 344	$ 394