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
	Mar. 31, 2023	Mar. 31, 2022
Net income	$ 552,000	$ 1,522,000
Shares (denominator):
Basic weighted average common shares outstanding (in shares)	12,150,067	13,058,871
Add: dilutive effect of common stock options (in shares)	43,535	100,619
Diluted weighted average common shares outstanding (in shares)	12,193,602	13,159,490
Earnings per common share:
Basic earnings per common share (in dollars per share)	$ 0.05	$ 0.12
Diluted earnings per common share (in dollars per share)	$ 0.05	$ 0.12