Note 17 - Earnings Per Common Share - Earnings Per Common Share and Diluted Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net income (numerator)	$ 21,720	$ 22,063	$ 22,579	$ 20,147	$ 23,838	$ 20,051	$ 19,562	$ 16,962	$ 20,728	$ 20,390	$ 19,625	$ 19,646	$ 86,509	$ 80,413	$ 80,389
Weighted average number of common shares outstanding - basic (denominator) (in shares)													26,855	26,942	26,956
Basic earnings per common share (in dollars per share)	$ 0.81	$ 0.82	$ 0.84	$ 0.75	$ 0.89	$ 0.74	$ 0.72	$ 0.63	$ 0.77	$ 0.76	$ 0.73	$ 0.73	$ 3.22	$ 2.98	$ 2.98
Add common stock equivalents for options (in shares)													15	18	50
Weighted average number of common shares outstanding - diluted (denominator) (in shares)													26,870	26,960	27,006
Diluted earnings per common share (in dollars per share)	$ 0.81	$ 0.82	$ 0.84	$ 0.75	$ 0.89	$ 0.74	$ 0.72	$ 0.63	$ 0.77	$ 0.75	$ 0.73	$ 0.73	$ 3.22	$ 2.98	$ 2.98