Note 3 - Earnings Per Share - Earnings Per Share Calculation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator for basic and diluted earnings per share – Net income available to common shareholders	$ 79,132	$ 80,278	$ 229,401	$ 269,008
Denominator for basic earnings per share – weighted average shares outstanding (in shares)	79,216	81,229	78,878	81,629
Employee and director stock options and restricted share awards (in shares)	2,668	2,758	2,729	2,622
Denominator for diluted earnings per share – adjusted weighted average shares outstanding and assumed conversions (in shares)	81,884	83,987	81,607	84,251
Basic earnings per common share (in dollars per share)	$ 1	$ 0.99	$ 2.91	$ 3.3
Diluted earnings per common share and common share equivalents (in dollars per share)	$ 0.97	$ 0.96	$ 2.81	$ 3.19