Note 2 - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2023		Sep. 30, 2023		Jun. 30, 2023		Mar. 31, 2023		Dec. 31, 2022		Sep. 30, 2022		Jun. 30, 2022		Mar. 31, 2022		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Earnings Per Share [Abstract]
Numerator for basic and diluted earnings per share - net income	$ 1,134		$ 2,344		$ 1,887		$ 4,118		$ 5,447		$ 3,415		$ 3,349		$ 3,710		$ 9,483	$ 15,921	$ 16,492
Denominator for basic earnings per share - weighted average shares outstanding																	3,610,713	3,564,481	3,553,949
Effect of dilutive securities - employee stock options																			189
Denominator for diluted earnings per share - adjusted weighted average shares outstanding																	3,610,713	3,564,481	3,554,138
Earnings per share - basic	$ 0.31	[1]	$ 0.65	[1]	$ 0.52	[1]	$ 1.15	[1]	$ 1.52	[1]	$ 0.96	[1]	$ 0.94	[1]	$ 1.04	[1]	$ 2.63	$ 4.47	$ 4.64
Earnings per share - diluted	$ 0.31	[1]	$ 0.65	[1]	$ 0.52	[1]	$ 1.15	[1]	$ 1.52	[1]	$ 0.96	[1]	$ 0.94	[1]	$ 1.04	[1]	$ 2.63	$ 4.47	$ 4.64

[1] Due to rounding, quarterly earnings per share may not sum to annual earnings per share