Note 9 - Earnings Per Share - Net Income Per Share Computation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Net income	$ 8,322	$ 8,539	$ 8,944	$ 9,232	$ 16,861	$ 18,176
Allocation of distributed and undistributed income to unvested restricted stock shareholders	(4)		(5)		(9)	(10)
Net income attributable to common shareholders	$ 8,318		$ 8,939		$ 16,852	$ 18,166
Weighted average common shares outstanding – basic (in shares)	25,083		25,426		25,166	25,420
Net income per share – basic (in dollars per share)	$ 0.33		$ 0.35		$ 0.67	$ 0.71
Net income attributable to common shareholders for basic computation	$ 8,318		$ 8,939		$ 16,852	$ 18,166
Weighted average effect of dilutive securities – stock options (in shares)	128		219		134	236
Denominator for diluted earnings per share – adjusted weighted average shares (in shares)	25,211		25,645		25,300	25,656
Net income per share - diluted (in dollars per share)	$ 0.33		$ 0.35		$ 0.67	$ 0.71