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 [Member]
Total shareholders’ equity at beginning of period at Dec. 31, 2020	$ 4,293,016	$ 145,452	$ 642	$ 997,168	$ 2,750,723	$ 512,970	$ (113,939)
Net income	116,015				116,015
Other comprehensive income (loss)	(125,222)					(125,222)
Stock option exercises/stock unit conversions (115,430 shares YTD in 2022 and 513,824 shares YTD in 2021)	29,397				(21,342)		50,739
Stock compensation expense recognized in earnings	2,526			2,526
Purchase of treasury stock (7,459 shares YTD in 2022 and 11,625 shares YTD in 2021)	(1,288)						(1,288)
Treasury stock issued to the 401(k) stock purchase plan (18,555 shares YTD in 2021 )	1,749				(57)		1,806
Cash dividends – preferred stock (approximately $11.13 per share which is equivalent to approximately $0.28 per depository share YTD in 2022 and $14.34 per share which is equivalent to approximately $0.36 per depository share YTD in 2021)	(2,151)				(2,151)
Cash dividends – common stock ($0.75 per share YTD in 2022 and $0.72 per share YTD in 2021)	(46,124)				(46,124)
Total shareholders’ equity at end of period at Mar. 31, 2021	4,267,918	145,452	642	999,694	2,797,064	387,748	(62,682)
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	99,102				99,102
Other comprehensive income (loss)	(719,108)					(719,108)
Stock option exercises/stock unit conversions (115,430 shares YTD in 2022 and 513,824 shares YTD in 2021)	5,739				(3,314)		9,053
Stock compensation expense recognized in earnings	2,112			2,112
Purchase of treasury stock (7,459 shares YTD in 2022 and 11,625 shares YTD in 2021)	(996)						(996)
Treasury stock issued to the 401(k) stock purchase plan (18,555 shares YTD in 2021 )	0
Cash dividends – preferred stock (approximately $11.13 per share which is equivalent to approximately $0.28 per depository share YTD in 2022 and $14.34 per share which is equivalent to approximately $0.36 per depository share YTD in 2021)	(1,669)				(1,669)
Cash dividends – common stock ($0.75 per share YTD in 2022 and $0.72 per share YTD in 2021)	(48,443)				(48,443)
Total shareholders’ equity at end of period at Mar. 31, 2022	$ 3,776,292	$ 145,452	$ 642	$ 1,012,033	$ 3,002,642	$ (371,790)	$ (12,687)