Note 18 - Stockholders' Equity (Details Textual) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended		18 Months Ended
	Feb. 21, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Equity, Attributable to Parent		$ 2,602,671	$ 2,431,532	$ 2,602,671	$ 2,431,532	$ 2,602,671	$ 2,542,339	$ 2,474,040	$ 2,422,230	$ 2,446,251
Stockholders' Equity, Period Increase (Decrease)						128,600
Net Income (Loss) Attributable to Parent		93,220	88,978	189,227	164,006	189,200
Other Comprehensive Income (Loss), Net of Tax		(7,972)	(25,351)	3,246	(68,263)	3,200
Share-Based Payment Arrangement, Noncash Expense						3,000
Proceeds from Issuance of Common Stock, Dividend Reinvestment Plan				1,835	1,873	1,800
Stock Issued During Period, Value, Issued for Services		849	849	850	849	900
Dividends, Common Stock, Cash		24,661	25,537	49,266	51,052	49,300
Treasury Stock, Value, Acquired, Cost Method	$ 16,600	44	30,588	16,692	63,484	16,700
Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation		$ 3,512	$ 1,730	$ 3,527	$ 2,015	$ 3,500