Note 9 - Earnings Per Share - Net Income Per Share Computation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Net income	$ 8,298	$ 8,322	$ 8,539	$ 9,657	$ 8,944	$ 9,232	$ 25,159	$ 27,833
Allocation of distributed and undistributed income to unvested restricted stock shareholders	(4)			(5)			(12)	(14)
Net income attributable to common shareholders	$ 8,294			$ 9,652			$ 25,147	$ 27,819
Weighted average common shares outstanding – basic (in shares)	24,716			25,427			25,014	25,423
Net income per share – basic (in dollars per share)	$ 0.34			$ 0.38			$ 1.01	$ 1.09
Net income attributable to common shareholders for basic computation	$ 8,294			$ 9,652			$ 25,147	$ 27,819
Weighted average effect of dilutive securities – stock options (in shares)	131			223			133	232
Denominator for diluted earnings per share – adjusted weighted average shares (in shares)	24,847			25,650			25,147	25,655
Net income per share - diluted (in dollars per share)	$ 0.33			$ 0.38			$ 1.00	$ 1.08