Note 9 - Earnings Per Share - Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Consolidated net income	$ 11,144	$ 9,031
Denominator – Weighted average number of common shares outstanding (in shares)	11,079,350	10,864,866
Basic earnings per common share (in dollars per share)	$ 1.01	$ 0.83
Numerator – Earnings available to common stockholders	$ 11,144	$ 9,031
Dilutive effect of stock options (in shares)	29,216	21,590
Weighted average diluted common shares outstanding (in shares)	11,108,566	10,886,456
Diluted earnings per common share (in dollars per share)	$ 1.00	$ 0.83