Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock, Common
Total shareholders’ equity at beginning of period at Dec. 31, 2022	$ 3,137,228	$ 145,452	$ 643	$ 1,029,756	$ 3,309,671	$ (1,348,294)	$ 0
Net income	495,422				495,422
Other comprehensive income (loss)	(430,533)					(430,533)
Stock option exercises/stock unit conversions (131,465 shares QTD and 254,093 shares YTD in 2024 and 8,483 shares QTD and 72,496 shares YTD in 2023)	3,042		1	1,463	(736)		2,314
Stock compensation expense recognized in earnings	12,646			12,646
Purchase of treasury stock (188,889 shares QTD and 508,176 shares YTD in 2024 and 111,956 shares QTD and 410,288 shares YTD in 2023)	(40,496)						(40,496)
Cash dividends – preferred stock (approximately $11.13 per share which is equivalent to approximately $0.28 per depository share QTD and $33.38 per share which is equivalent to approximately $0.83 per depository share YTD in both 2024 and 2023, respectively.)	(5,006)				(5,006)
Cash dividends – common stock ($0.95 per share QTD and $2.79 per share YTD in 2024 and $0.92 per share QTD and $2.66 per share YTD in 2023)	(172,552)				(172,552)
Total shareholders’ equity at end of period at Sep. 30, 2023	2,999,751	145,452	644	1,043,865	3,626,799	(1,778,827)	(38,182)
Total shareholders’ equity at beginning of period at Dec. 31, 2022	3,137,228	145,452	643	1,029,756	3,309,671	(1,348,294)	0
Total shareholders’ equity at end of period at Dec. 31, 2023	3,716,447	145,452	644	1,055,809	3,657,688	(1,119,219)	(23,927)
Total shareholders’ equity at beginning of period at Jun. 30, 2023	3,386,742	145,452	644	1,040,754	3,532,542	(1,305,027)	(27,623)
Net income	155,651				155,651
Other comprehensive income (loss)	(473,800)					(473,800)
Stock option exercises/stock unit conversions (131,465 shares QTD and 254,093 shares YTD in 2024 and 8,483 shares QTD and 72,496 shares YTD in 2023)	596				(217)		813
Stock compensation expense recognized in earnings	3,111			3,111
Purchase of treasury stock (188,889 shares QTD and 508,176 shares YTD in 2024 and 111,956 shares QTD and 410,288 shares YTD in 2023)	(11,372)						(11,372)
Cash dividends – preferred stock (approximately $11.13 per share which is equivalent to approximately $0.28 per depository share QTD and $33.38 per share which is equivalent to approximately $0.83 per depository share YTD in both 2024 and 2023, respectively.)	(1,668)				(1,668)
Cash dividends – common stock ($0.95 per share QTD and $2.79 per share YTD in 2024 and $0.92 per share QTD and $2.66 per share YTD in 2023)	(59,509)				(59,509)
Total shareholders’ equity at end of period at Sep. 30, 2023	2,999,751	145,452	644	1,043,865	3,626,799	(1,778,827)	(38,182)
Total shareholders’ equity at beginning of period at Dec. 31, 2023	3,716,447	145,452	644	1,055,809	3,657,688	(1,119,219)	(23,927)
Net income	427,690				427,690
Other comprehensive income (loss)	203,786					203,786
Stock option exercises/stock unit conversions (131,465 shares QTD and 254,093 shares YTD in 2024 and 8,483 shares QTD and 72,496 shares YTD in 2023)	15,484				(10,043)		25,527
Stock compensation expense recognized in earnings	10,020			10,020
Purchase of treasury stock (188,889 shares QTD and 508,176 shares YTD in 2024 and 111,956 shares QTD and 410,288 shares YTD in 2023)	(52,273)						(52,273)
Cash dividends – preferred stock (approximately $11.13 per share which is equivalent to approximately $0.28 per depository share QTD and $33.38 per share which is equivalent to approximately $0.83 per depository share YTD in both 2024 and 2023, respectively.)	(5,006)				(5,006)
Cash dividends – common stock ($0.95 per share QTD and $2.79 per share YTD in 2024 and $0.92 per share QTD and $2.66 per share YTD in 2023)	(180,942)				(180,942)
Total shareholders’ equity at end of period at Sep. 30, 2024	4,135,206	145,452	644	1,065,829	3,889,387	(915,433)	(50,673)
Total shareholders’ equity at beginning of period at Jun. 30, 2024	3,665,805	145,452	644	1,064,070	3,810,008	(1,309,344)	(45,025)
Net income	146,501				146,501
Other comprehensive income (loss)	393,911					393,911
Stock option exercises/stock unit conversions (131,465 shares QTD and 254,093 shares YTD in 2024 and 8,483 shares QTD and 72,496 shares YTD in 2023)	10,275				(4,124)		14,399
Stock compensation expense recognized in earnings	1,759			1,759
Purchase of treasury stock (188,889 shares QTD and 508,176 shares YTD in 2024 and 111,956 shares QTD and 410,288 shares YTD in 2023)	(20,047)						(20,047)
Cash dividends – preferred stock (approximately $11.13 per share which is equivalent to approximately $0.28 per depository share QTD and $33.38 per share which is equivalent to approximately $0.83 per depository share YTD in both 2024 and 2023, respectively.)	(1,668)				(1,668)
Cash dividends – common stock ($0.95 per share QTD and $2.79 per share YTD in 2024 and $0.92 per share QTD and $2.66 per share YTD in 2023)	(61,330)				(61,330)
Total shareholders’ equity at end of period at Sep. 30, 2024	$ 4,135,206	$ 145,452	$ 644	$ 1,065,829	$ 3,889,387	$ (915,433)	$ (50,673)