Note 4 -Earnings Per Share - Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net earnings for the quarter	$ 10,266	$ 7,972	$ 28,072	$ 22,761
Denominator – Weighted average number of common shares outstanding (in shares)	10,766,738	10,601,882	10,729,065	10,544,584
Basic earnings per common share (in dollars per share)	$ 0.95	$ 0.75	$ 2.62	$ 2.16
Numerator – Earnings available to common stockholders	$ 10,266	$ 7,972	$ 28,072	$ 22,761
Dilutive effect of stock options (in shares)	20,014	9,884	17,065	6,952
Weighted average diluted common shares outstanding (in shares)	10,786,752	10,611,766	10,746,130	10,551,536
Diluted earnings per common share (in dollars per share)	$ 0.95	$ 0.75	$ 2.61	$ 2.16