Consolidated Statement of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss), Net of Tax [Member]	Treasury Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting change	$ (14,672)				$ (14,672)
Adjusted beginning balance	3,354,245	$ 144,486	$ 642	$ 967,304	2,425,330	$ (63,600)	$ (119,917)
Balance at Dec. 31, 2018	3,368,917	144,486	642	967,304	2,440,002	(63,600)	(119,917)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	443,599				443,599
Other comprehensive income, net of tax	330,970					330,970
Proceeds from stock option exercises/stock unit conversions (987,758 shares, 408,563 shares, and 399,224 shares during 2021, 2020, and 2019, respectively)	20,770				(16,326)		37,096
Stock-based compensation expense recognized in earnings	15,946			15,946
Purchase of treasury stock (31,317 shares, 206,951 shares, and 716,062 shares during 2021, 2020, and 2019, respectively)	(68,793)						(68,793)
Treasury Stock issued to the 401(k) stock purchase plan (18,555 shares in 2021 and 140,264 shares in 2020)	0
Cash dividends paid on preferred stock (approximately $47.71 per share which is equivalent to approximately $1.19 per depositary share in 2021 and approximately $0.34 per share in 2020 and $1.34 per share in 2019)	(8,063)				(8,063)
Cash dividends – common stock ($2.94 per share, $2.85 per share, and $2.80 per share in 2021, 2020, and 2019, respectively)	(177,006)				(177,006)
Balance at Dec. 31, 2019	3,911,668	144,486	642	983,250	2,667,534	267,370	(151,614)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting change	(29,252)				(29,252)
Adjusted beginning balance	3,882,416	144,486	642	983,250	2,638,282	267,370	(151,614)
Net income	331,151				331,151
Other comprehensive income, net of tax	245,600					245,600
Proceeds from stock option exercises/stock unit conversions (987,758 shares, 408,563 shares, and 399,224 shares during 2021, 2020, and 2019, respectively)	12,557				(27,214)		39,771
Stock-based compensation expense recognized in earnings	13,918			13,918
Redemption of series A preferred stock (6,000,000 shares)	(150,000)	(144,486)			(5,514)
Issuance of series B preferred stock (150,000 shares)	145,452	145,452
Purchase of treasury stock (31,317 shares, 206,951 shares, and 716,062 shares during 2021, 2020, and 2019, respectively)	(15,785)						(15,785)
Treasury Stock issued to the 401(k) stock purchase plan (18,555 shares in 2021 and 140,264 shares in 2020)	10,307				(3,382)		13,689
Cash dividends paid on preferred stock (approximately $47.71 per share which is equivalent to approximately $1.19 per depositary share in 2021 and approximately $0.34 per share in 2020 and $1.34 per share in 2019)	(2,016)				(2,016)
Cash dividends – common stock ($2.94 per share, $2.85 per share, and $2.80 per share in 2021, 2020, and 2019, respectively)	(180,584)				(180,584)
Balance at Dec. 31, 2020	4,293,016	145,452	642	997,168	2,750,723	512,970	(113,939)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	443,079				443,079
Other comprehensive income, net of tax	(165,652)					(165,652)
Proceeds from stock option exercises/stock unit conversions (987,758 shares, 408,563 shares, and 399,224 shares during 2021, 2020, and 2019, respectively)	54,417				(40,836)		95,253
Stock-based compensation expense recognized in earnings	12,753			12,753
Purchase of treasury stock (31,317 shares, 206,951 shares, and 716,062 shares during 2021, 2020, and 2019, respectively)	(3,864)						(3,864)
Treasury Stock issued to the 401(k) stock purchase plan (18,555 shares in 2021 and 140,264 shares in 2020)	1,749				(57)		1,806
Cash dividends paid on preferred stock (approximately $47.71 per share which is equivalent to approximately $1.19 per depositary share in 2021 and approximately $0.34 per share in 2020 and $1.34 per share in 2019)	(7,157)				(7,157)
Cash dividends – common stock ($2.94 per share, $2.85 per share, and $2.80 per share in 2021, 2020, and 2019, respectively)	(188,786)				(188,786)
Balance at Dec. 31, 2021	$ 4,439,555	$ 145,452	$ 642	$ 1,009,921	$ 2,956,966	$ 347,318	$ (20,744)