Note 11 - 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		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Net income applicable to common equity (numerator)	$ 41,601	$ 34,760	$ 122,300	$ 82,690
Weighted average number of common shares outstanding - basic (denominator) (in shares)	26,648	26,906	26,718	26,889
Basic earnings per common share (in dollars per share)	$ 1.56	$ 1.29	$ 4.58	$ 3.08
Add common stock equivalents for options (in shares)	2	10	3	12
Weighted average number of common shares outstanding - diluted (denominator) (in shares)	26,650	26,916	26,721	26,901
Diluted earnings per common share (in dollars per share)	$ 1.56	$ 1.29	$ 4.58	$ 3.07