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, 2021	$ 4,439,555	$ 145,452	$ 642	$ 1,009,921	$ 2,956,966	$ 347,318	$ (20,744)
Net income	387,976				387,976
Other comprehensive income (loss)	(1,876,243)					(1,876,243)
Stock option exercises/stock unit conversions (8,483 shares QTD and 72,496 shares YTD in 2023 and 88,350 shares QTD and 232,612 shares YTD in 2022)	11,760				(6,695)		18,455
Stock compensation expense recognized in earnings	8,703			8,703
Purchase of treasury stock (111,956 shares QTD and 410,288 shares YTD in 2023 and 7,459 shares YTD in 2022)	(996)						(996)
Cash dividends – preferred stock (approximately $11.13 per share which is equivalent to approximately $0.28 per depository share QTD in 2023 and 2022, respectively and approximately $33.38 per share which is equivalent to approximately $0.83 per depository share YTD in 2023 and 2022, respectively )	(5,006)				(5,006)
Cash dividends – common stock ($0.92 per share QTD and $2.66 per share YTD in 2023 and $0.87 per share QTD and $2.37 per share YTD in 2022)	(153,277)				(153,277)
Total shareholders’ equity at end of period at Sep. 30, 2022	2,812,472	145,452	642	1,018,624	3,179,964	(1,528,925)	(3,285)
Total shareholders’ equity at beginning of period at Jun. 30, 2022	3,346,975	145,452	642	1,015,451	3,070,109	(874,206)	(10,473)
Net income	169,760				169,760
Other comprehensive income (loss)	(654,719)					(654,719)
Stock option exercises/stock unit conversions (8,483 shares QTD and 72,496 shares YTD in 2023 and 88,350 shares QTD and 232,612 shares YTD in 2022)	5,270				(1,918)		7,188
Stock compensation expense recognized in earnings	3,173			3,173
Cash dividends – preferred stock (approximately $11.13 per share which is equivalent to approximately $0.28 per depository share QTD in 2023 and 2022, respectively and approximately $33.38 per share which is equivalent to approximately $0.83 per depository share YTD in 2023 and 2022, respectively )	(1,668)				(1,668)
Cash dividends – common stock ($0.92 per share QTD and $2.66 per share YTD in 2023 and $0.87 per share QTD and $2.37 per share YTD in 2022)	(56,319)				(56,319)
Total shareholders’ equity at end of period at Sep. 30, 2022	2,812,472	145,452	642	1,018,624	3,179,964	(1,528,925)	(3,285)
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 (8,483 shares QTD and 72,496 shares YTD in 2023 and 88,350 shares QTD and 232,612 shares YTD in 2022)	3,042		1	1,463	(736)		2,314
Stock compensation expense recognized in earnings	12,646			12,646
Purchase of treasury stock (111,956 shares QTD and 410,288 shares YTD in 2023 and 7,459 shares YTD in 2022)	(40,496)						(40,496)
Cash dividends – preferred stock (approximately $11.13 per share which is equivalent to approximately $0.28 per depository share QTD in 2023 and 2022, respectively and approximately $33.38 per share which is equivalent to approximately $0.83 per depository share YTD in 2023 and 2022, respectively )	(5,006)				(5,006)
Cash dividends – common stock ($0.92 per share QTD and $2.66 per share YTD in 2023 and $0.87 per share QTD and $2.37 per share YTD in 2022)	(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 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 (8,483 shares QTD and 72,496 shares YTD in 2023 and 88,350 shares QTD and 232,612 shares YTD in 2022)	596				(217)		813
Stock compensation expense recognized in earnings	3,111			3,111
Purchase of treasury stock (111,956 shares QTD and 410,288 shares YTD in 2023 and 7,459 shares YTD in 2022)	(11,372)						(11,372)
Cash dividends – preferred stock (approximately $11.13 per share which is equivalent to approximately $0.28 per depository share QTD in 2023 and 2022, respectively and approximately $33.38 per share which is equivalent to approximately $0.83 per depository share YTD in 2023 and 2022, respectively )	(1,668)				(1,668)
Cash dividends – common stock ($0.92 per share QTD and $2.66 per share YTD in 2023 and $0.87 per share QTD and $2.37 per share YTD in 2022)	(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)