Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment		Common Stock	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment		Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjustment	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative adjustment	$ 3,969,367	$ 0	[1]	$ 3,517,258	$ 477,101	$ (9,710)	[1]	$ (24,992)	$ 9,710
Balance, shares at Dec. 31, 2017				220,148,824
Balance, value at Dec. 31, 2017	3,969,367	0	[1]	$ 3,517,258	477,101	(9,710)	[1]	(24,992)	9,710
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss) Attributable to Parent	316,263				316,263
Other comprehensive loss, net of tax	(43,632)							(43,632)
Stock-based compensation	7,513			$ 7,513
Stock repurchased and retired, shares				(557,648)
Stock repurchased and retired	(12,962)			$ (12,962)
Issuances of common stock under stock plans, shares				663,863
Issuances of common stock under stock plans	1,065			$ 1,065
Cash dividends on common stock	(181,172)				(181,172)
Cumulative adjustment	$ 4,056,442	(244)	[2]	$ 3,512,874	602,482	(244)	[2]	(58,914)	$ 9,710
Cash dividends on common stock (in usd per share)	$ 0.82
Balance, shares at Dec. 31, 2018				220,255,039
Balance, value at Dec. 31, 2018	$ 4,056,442	(244)	[2]	$ 3,512,874	602,482	(244)	[2]	(58,914)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative adjustment	4,056,442	(244)	[2]	3,512,874	602,482	(244)	[2]	(58,914)
Net Income (Loss) Attributable to Parent	354,095				354,095
Other comprehensive loss, net of tax	88,463							88,463
Stock-based compensation	8,373			$ 8,373
Stock repurchased and retired, shares				(415,403)
Stock repurchased and retired	(7,268)			$ (7,268)
Issuances of common stock under stock plans, shares				389,646
Issuances of common stock under stock plans	21			$ 21
Cash dividends on common stock	(185,967)				(185,967)
Cumulative adjustment	$ 4,313,915	(40,181)	[3]	$ 3,514,000	770,366	(40,181)	[3]	29,549
Cash dividends on common stock (in usd per share)	$ 0.84
Balance, shares at Dec. 31, 2019	220,229,282			220,229,282
Balance, value at Dec. 31, 2019	$ 4,313,915	(40,181)	[3]	$ 3,514,000	770,366	(40,181)	[3]	29,549
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative adjustment	4,313,915	(40,181)	[3]	3,514,000	770,366	(40,181)	[3]	29,549
Net Income (Loss) Attributable to Parent	(1,523,420)				(1,523,420)
Other comprehensive loss, net of tax	93,196							93,196
Stock-based compensation	9,254			$ 9,254
Stock repurchased and retired, shares				(494,009)
Stock repurchased and retired	(8,655)			$ (8,655)
Issuances of common stock under stock plans, shares				491,062
Issuances of common stock under stock plans	0			$ 0
Cash dividends on common stock	(139,532)				(139,532)
Cumulative adjustment	$ 2,704,577	$ (40,181)	[3]	$ 3,514,599	(932,767)	$ (40,181)	[3]	122,745
Cash dividends on common stock (in usd per share)	$ 0.63
Balance, shares at Dec. 31, 2020	220,226,335			220,226,335
Balance, value at Dec. 31, 2020	$ 2,704,577			$ 3,514,599	(932,767)			122,745
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative adjustment	$ 2,704,577			$ 3,514,599	$ (932,767)			$ 122,745

[1] The cumulative effect adjustment from retained earnings to accumulated other comprehensive income (loss) related to the implementation of new accounting guidance on January 1, 2018, for the junior subordinated debentures that the Company previously elected to fair value on a recurring basis.

[2] The cumulative effect adjustment relates to the implementation of new accounting guidance on January 1, 2019 for operating leases.

[3] The cumulative effect adjustment relates to the implementation of new accounting guidance on January 1, 2020, for the allowance for credit losses. Refer to Note 1 for discussion of the new accounting guidance.