Note 8 - Basic and Diluted Earnings Per Common Share - Reconciliation of Net Income and Number of Shares Used in Computations of Basic and Diluted EPS (Details) - USD ($)	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Net income	$ 1,146,000	$ 552,000	$ 693,000	$ 1,522,000	$ 1,698,000	$ 2,215,000
Shares (denominator):
Basic weighted average common shares outstanding (in shares)	11,997,443		12,834,332		12,072,571	12,945,981
Add: dilutive effect of common stock options (in shares)	16,402		73,891		30,848	86,332
Diluted weighted average common shares outstanding (in shares)	12,013,845		12,908,223		12,103,419	13,032,313
Earnings per common share:
Basic earnings per common share (in dollars per share)	$ 0.10		$ 0.05		$ 0.14	$ 0.17
Diluted earnings per common share (in dollars per share)	$ 0.10		$ 0.05		$ 0.14	$ 0.17