Note 12 - Earnings Per Share - Earnings Per Share Calculation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Numerator for basic and diluted earnings per share − Net income available to common shareholders	$ 391,382	$ 241,415	$ 114,887
Denominator for basic earnings per share – weighted average shares outstanding (in shares)	55,400	55,892	54,866
Effect of dilutive securities− Employee and director stock options and restricted share awards (in shares)	1,751	1,986	1,376
Denominator for diluted earnings per share − adjusted weighted average shares outstanding and assumed conversions (in shares)	57,151	57,878	56,242
Basic earnings per common share (in dollars per share)	$ 7.06	$ 4.32	$ 2.09
Diluted earnings per common share and common share equivalents (in dollars per share)	$ 6.85	$ 4.17	$ 2.04