Note 12 - Earnings Per Share - Earnings Per Share Calculation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Numerator for basic and diluted earnings per share − Net income available to common shareholders	$ 347,055	$ 391,382	$ 241,415
Denominator for basic earnings per share – weighted average shares outstanding (in shares)	81,089	83,100	83,838
Effect of dilutive securities− Employee and director stock options and restricted share awards (in shares)	2,631	2,627	2,979
Denominator for diluted earnings per share − adjusted weighted average shares outstanding and assumed conversions (in shares)	83,720	85,727	86,817
Basic earnings per common share (in dollars per share)	$ 4.28	$ 4.71	$ 2.88
Diluted earnings per common share and common share equivalents (in dollars per share)	$ 4.15	$ 4.57	$ 2.78