Consolidated Statement of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Share awards vesting Treasury Stock, Common	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, Common
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 (267,357 shares, 399,810 shares, and 987,758 shares during 2022, 2021, and 2020, respectively)	54,417					(40,836)		95,253
Stock-based compensation expense recognized in earnings	12,753				12,753
Purchase of treasury stock (436,765 shares, 31,351 shares, and 31,317 shares during 2022, 2021, and 2020, respectively)	(3,864)	$ (3,900)						(3,864)
Treasury Stock issued to the 401(k) stock purchase plan (18,555 shares in 2021)	1,749					(57)		1,806
Cash dividends paid on preferred stock (approximately $44.50 per share which is equivalent to approximately $1.11 per depositary share in 2023 and 2022 and approximately $47.71 per share which is equivalent to approximately $1.19 per share in 2021)	(7,157)					(7,157)
Cash dividends – common stock ($3.58 per share, $3.24 per share, and $2.94 per share in 2022, 2021, and 2020, 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)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury Stock, Shares, Acquired	0	31,317
Net income	$ 579,150					579,150
Other comprehensive income, net of tax	(1,695,612)						(1,695,612)
Proceeds from stock option exercises/stock unit conversions (267,357 shares, 399,810 shares, and 987,758 shares during 2022, 2021, and 2020, respectively)	16,659			1	1,513	(9,990)		25,135
Stock-based compensation expense recognized in earnings	18,322				18,322
Purchase of treasury stock (436,765 shares, 31,351 shares, and 31,317 shares during 2022, 2021, and 2020, respectively)	(4,391)	$ (4,400)						(4,391)
Treasury Stock issued to the 401(k) stock purchase plan (18,555 shares in 2021)	0
Cash dividends paid on preferred stock (approximately $44.50 per share which is equivalent to approximately $1.11 per depositary share in 2023 and 2022 and approximately $47.71 per share which is equivalent to approximately $1.19 per share in 2021)	(6,675)					(6,675)
Cash dividends – common stock ($3.58 per share, $3.24 per share, and $2.94 per share in 2022, 2021, and 2020, respectively)	(209,780)					(209,780)
Balance at Dec. 31, 2022	$ 3,137,228		145,452	643	1,029,756	3,309,671	(1,348,294)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury Stock, Shares, Acquired	0	31,351
Net income	$ 597,973					597,973
Other comprehensive income, net of tax	229,075						229,075
Proceeds from stock option exercises/stock unit conversions (267,357 shares, 399,810 shares, and 987,758 shares during 2022, 2021, and 2020, respectively)	9,299			1	1,463	(10,958)		18,793
Stock-based compensation expense recognized in earnings	24,590				24,590
Purchase of treasury stock (436,765 shares, 31,351 shares, and 31,317 shares during 2022, 2021, and 2020, respectively)	(42,720)	$ (3,500)						(42,720)
Treasury Stock issued to the 401(k) stock purchase plan (18,555 shares in 2021)	0
Cash dividends paid on preferred stock (approximately $44.50 per share which is equivalent to approximately $1.11 per depositary share in 2023 and 2022 and approximately $47.71 per share which is equivalent to approximately $1.19 per share in 2021)	(6,675)					(6,675)
Cash dividends – common stock ($3.58 per share, $3.24 per share, and $2.94 per share in 2022, 2021, and 2020, respectively)	(232,323)					(232,323)
Balance at Dec. 31, 2023	$ 3,716,447		$ 145,452	$ 644	$ 1,055,809	$ 3,657,688	$ (1,119,219)	$ (23,927)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury Stock, Shares, Acquired	436,765	35,897