Note 9 - Earnings Per Share - Net Income Per Share Computation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Net income	$ 8,539	$ 9,232
Allocation of distributed and undistributed income to unvested restricted stock shareholders	(5)	(6)
Net income attributable to common shareholders	$ 8,534	$ 9,226
Weighted average common shares outstanding – basic (in shares)	25,251	25,414
Net income per share – basic (in dollars per share)	$ 0.34	$ 0.36
Net income attributable to common shareholders for basic computation	$ 8,534	$ 9,226
Weighted average effect of dilutive securities – stock options (in shares)	139	254
Denominator for diluted earnings per share – adjusted weighted average shares (in shares)	25,390	25,668
Net income per share - diluted (in dollars per share)	$ 0.34	$ 0.36