Note 18 - Stockholders' Equity (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Stockholders' Equity Attributable to Parent, Ending Balance	$ 2,419,559	$ 2,463,291	$ 2,419,559	$ 2,463,291	$ 2,431,532	$ 2,446,251	$ 2,452,357	$ 2,418,144
Stockholders' Equity, Period Increase (Decrease), Total			26,700
Net Income (Loss) Attributable to Parent, Total	99,035	72,397	263,041	222,980
Share-Based Payment Arrangement, Noncash Expense, Total			5,200
Proceeds from Issuance of Common Stock, Dividend Reinvestment Plan			2,793	2,619
Stock Issued During Period, Value, Issued for Services			849	850
Other Comprehensive Income (Loss), Net of Tax, Total	(41,546)	(2,740)	(109,809)	(5,678)
Treasury Stock, Value, Acquired, Cost Method	46,290	37,139	109,774	100,668
Dividends, Common Stock, Cash	25,059	24,137	76,111	73,335
Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation	$ 849	$ 38	$ 2,864	$ 2,632