Consolidated Statement of Changes in Stockholders' Equity - Unaudited - USD ($) $ in Thousands	Total	Cumulative Effect, Period Of Adoption, Adjustment	[1]	Common Stock	Common Stock and Additional Paid-In Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period Of Adoption, Adjustment	[1]	Treasury Stock	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	244,176					244,176
Other comprehensive income	41,542									41,542
Net activity of common stock pursuant to various stock compensation plans and agreements (in shares)				332,694
Net activity of common stock pursuant to various stock compensation plans and agreements	7,778				15,403				(7,625)
Repurchase of common stock pursuant to the Stock Repurchase Program (in shares)				(4,471,682)
Repurchase of common stock pursuant to the Stock Repurchase Program	(145,966)								(145,966)
Cash dividends on common stock	(79,937)					(79,937)
Ending balance (in shares) at Jun. 30, 2020				141,486,397
Ending balance at Jun. 30, 2020	4,987,243				1,841,915	3,755,649			(633,455)	23,134
Beginning balance (in shares) at Mar. 31, 2020				141,435,099
Beginning balance at Mar. 31, 2020	4,902,985				1,833,784	3,695,759			(633,439)	6,881
Increase (Decrease) in Stockholders' Equity
Net income	99,352					99,352
Other comprehensive income	16,253									16,253
Net activity of common stock pursuant to various stock compensation plans and agreements (in shares)				51,298
Net activity of common stock pursuant to various stock compensation plans and agreements	8,115				8,131				(16)
Cash dividends on common stock	(39,462)					(39,462)
Ending balance (in shares) at Jun. 30, 2020				141,486,397
Ending balance at Jun. 30, 2020	4,987,243				1,841,915	3,755,649			(633,455)	23,134
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	429,736					429,736
Other comprehensive income	(59,014)									(59,014)
Net activity of common stock pursuant to various stock compensation plans and agreements (in shares)				312,276
Net activity of common stock pursuant to various stock compensation plans and agreements	2,474				17,728				(15,254)
Cash dividends on common stock	(94,823)					(94,823)
Ending balance (in shares) at Jun. 30, 2021				141,877,505
Ending balance at Jun. 30, 2021	5,547,548				1,876,247	4,335,327			(649,337)	(14,689)
Beginning balance (in shares) at Mar. 31, 2021				141,843,036
Beginning balance at Mar. 31, 2021	5,285,027				1,866,101	4,158,032			(649,066)	(90,040)
Increase (Decrease) in Stockholders' Equity
Net income	224,742					224,742
Other comprehensive income	75,351									75,351
Net activity of common stock pursuant to various stock compensation plans and agreements (in shares)				34,469
Net activity of common stock pursuant to various stock compensation plans and agreements	9,875				10,146				(271)
Cash dividends on common stock	(47,447)					(47,447)
Ending balance (in shares) at Jun. 30, 2021				141,877,505
Ending balance at Jun. 30, 2021	$ 5,547,548				$ 1,876,247	$ 4,335,327			$ (649,337)	$ (14,689)

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