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, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net income (numerator)	$ 39,468	$ 41,601	$ 40,248	$ 40,451	$ 39,344	$ 34,760	$ 25,314	$ 22,616	$ 21,720	$ 22,063	$ 22,579	$ 20,147	$ 161,768	$ 122,034	$ 86,509
Weighted average number of common shares outstanding - basic (denominator) (in shares)													26,703	26,895	26,855
Basic earnings per common share (in dollars per share)	$ 1.48	$ 1.56	$ 1.51	$ 1.51	$ 1.46	$ 1.29	$ 0.94	$ 0.84	$ 0.81	$ 0.82	$ 0.84	$ 0.75	$ 6.06	$ 4.54	$ 3.22
Add common stock equivalents for options (in shares)													3	12	15
Weighted average number of common shares outstanding - diluted (denominator) (in shares)													26,706	26,907	26,870
Diluted earnings per common share (in dollars per share)	$ 1.48	$ 1.56	$ 1.51	$ 1.51	$ 1.46	$ 1.29	$ 0.94	$ 0.84	$ 0.81	$ 0.82	$ 0.84	$ 0.75	$ 6.06	$ 4.54	$ 3.22