Consolidated Statement of Changes in Stockholders' Equity - Unaudited - USD ($) $ in Thousands	Total	Stock Repurchase Program	Stock Compensation Plans and Agreements	Cumulative Effect, Period Of Adoption, Adjustment	[1]	Common Stock	Common Stock Stock Repurchase Program	Common Stock Stock Compensation Plans and Agreements	Common Stock and Additional Paid-In Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period Of Adoption, Adjustment	[1]	Treasury Stock	Treasury Stock Stock Repurchase Program	Treasury Stock Stock Compensation Plans and Agreements	AOCI, Net of Tax
Beginning balance (in shares) at Dec. 31, 2019						145,625,385
Beginning balance at Dec. 31, 2019	$ 5,017,617			$ (97,967)					$ 1,826,512	$ 3,689,377	$ (97,967)		$ (479,864)			$ (18,408)
Increase (Decrease) in Stockholders' Equity
Net income	403,713									403,713
Other comprehensive income	51,722															51,722
Issuance of common stock pursuant to various stock compensation plans and agreements (in shares)						543,287
Issuance of common stock pursuant to various stock compensation plans and agreements	24,051								24,051				0
Repurchase of common stock pursuant to the Stock Repurchase Program (in shares)							(4,471,682)	(189,560)
Repurchase of common stock pursuant to the Stock Repurchase Program		$ (145,966)	$ (7,656)											$ (145,966)	$ (7,656)
Cash dividends on common stock	(119,408)									(119,408)
Ending balance (in shares) at Sep. 30, 2020						141,507,430
Ending balance at Sep. 30, 2020	5,126,106								1,850,563	3,875,715			(633,486)			33,314
Beginning balance (in shares) at Jun. 30, 2020						141,486,397
Beginning balance at Jun. 30, 2020	4,987,243								1,841,915	3,755,649			(633,455)			23,134
Increase (Decrease) in Stockholders' Equity
Net income	159,537									159,537
Other comprehensive income	10,180															10,180
Issuance of common stock pursuant to various stock compensation plans and agreements (in shares)						21,968
Issuance of common stock pursuant to various stock compensation plans and agreements	8,648								8,648				0
Repurchase of common stock pursuant to the Stock Repurchase Program (in shares)								(935)
Repurchase of common stock pursuant to the Stock Repurchase Program	(31)														(31)
Cash dividends on common stock	(39,471)									(39,471)
Ending balance (in shares) at Sep. 30, 2020						141,507,430
Ending balance at Sep. 30, 2020	5,126,106								1,850,563	3,875,715			(633,486)			33,314
Beginning balance (in shares) at Dec. 31, 2020						141,565,229
Beginning balance at Dec. 31, 2020	5,269,175								1,858,519	4,000,414			(634,083)			44,325
Increase (Decrease) in Stockholders' Equity
Net income	655,185									655,185
Other comprehensive income	(101,893)															(101,893)
Issuance of common stock pursuant to various stock compensation plans and agreements (in shares)						523,449
Issuance of common stock pursuant to various stock compensation plans and agreements	25,520								25,520				0
Repurchase of common stock pursuant to the Stock Repurchase Program (in shares)								(204,947)
Repurchase of common stock pursuant to the Stock Repurchase Program	(15,508)														(15,508)
Cash dividends on common stock	(142,278)									(142,278)
Ending balance (in shares) at Sep. 30, 2021						141,883,731
Ending balance at Sep. 30, 2021	5,690,201								1,884,039	4,513,321			(649,591)			(57,568)
Beginning balance (in shares) at Jun. 30, 2021						141,877,505
Beginning balance at Jun. 30, 2021	5,547,548								1,876,247	4,335,327			(649,337)			(14,689)
Increase (Decrease) in Stockholders' Equity
Net income	225,449									225,449
Other comprehensive income	(42,879)															(42,879)
Issuance of common stock pursuant to various stock compensation plans and agreements (in shares)						9,643
Issuance of common stock pursuant to various stock compensation plans and agreements	7,792								7,792				0
Repurchase of common stock pursuant to the Stock Repurchase Program (in shares)								(3,417)
Repurchase of common stock pursuant to the Stock Repurchase Program	(254)														$ (254)
Cash dividends on common stock	(47,455)									(47,455)
Ending balance (in shares) at Sep. 30, 2021						141,883,731
Ending balance at Sep. 30, 2021	$ 5,690,201								$ 1,884,039	$ 4,513,321			$ (649,591)			$ (57,568)

[1] Represents the impact of the adoption of Accounting Standards Update (“ASU”) 2016-13, Financial Instruments — Credit Losses (Topic 326) on January 1, 2020.