Note 12 - Earnings Per Share - Earnings Per Share Calculation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net income available to common shareholders	$ 241,415	$ 114,887	$ 141,583
Denominator for basic earnings per share – weighted average shares outstanding (in shares)	55,892	54,866	54,988
Employee and director stock options and restricted share awards (in shares)	1,986	1,376	1,368
Denominator for diluted earnings per share - adjusted weighted average shares outstanding and assumed conversions (in shares)	57,878	56,242	56,356
Basic earnings per common share (in dollars per share)	$ 4.32	$ 2.09	$ 2.57
Diluted earnings per common share and common share equivalents (in dollars per share)	$ 4.17	$ 2.04	$ 2.51