Note 8 - 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, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Net income	$ 7,876	$ 7,273	$ 6,964	$ 8,298	$ 8,322	$ 8,539	$ 22,113	$ 25,159
Allocation of distributed and undistributed income to unvested restricted stock shareholders	(2)			(4)			(5)	(12)
Net income attributable to common shareholders	$ 7,874			$ 8,294			$ 22,108	$ 25,147
Basic (in shares)	24,560			24,716			24,574	25,014
Net income per share – basic (in dollars per share)	$ 0.32			$ 0.34			$ 0.9	$ 1.01
Net income attributable to common shareholders for basic computation	$ 7,874			$ 8,294			$ 22,108	$ 25,147
Weighted average common shares outstanding – basic (in shares)	24,560			24,716			24,574	25,014
Weighted average effect of dilutive securities – stock options (in shares)	135			131			141	133
Denominator for diluted earnings per share – adjusted weighted average shares (in shares)	24,695			24,847			24,715	25,147
Net income per share - diluted (in dollars per share)	$ 0.32			$ 0.33			$ 0.89	$ 1