Note 6 - Earnings Per Share - Calculation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net income	$ 3,692	$ 4,002	$ 10,193	$ 11,630
Basic earnings per share (in dollars per share)	$ 0.71	$ 0.78	$ 1.97	$ 2.26
Diluted earnings per share (in dollars per share)	$ 0.71	$ 0.77	$ 1.95	$ 2.22
Basic shares (in shares)	5,179	5,160	5,176	5,153
Diluted shares (in shares)	5,230	5,227	5,229	5,227