Consolidated Statements of Changes In Shareholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Class A Common Stock, Par Value $1	Class B Common Stock	Common Stock	Common Stock Class A Common Stock, Par Value $1	Common Stock Class B Common Stock	Preferred Stock	Surplus	Surplus Class A Common Stock, Par Value $1	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings Class A Common Stock, Par Value $1	Retained Earnings Class B Common Stock	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2018	$ 3,488,954					$ 10,623	$ 1,005	$ 0	$ 493,962		$ 3,218,551				$ (235,187)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	457,371										457,371
Other comprehensive income (loss), net of tax	108,464														108,464
Stock repurchases during period			$ 450,880			999				$ 449,881
Cash dividends	(1,608)		(16,117)								(1,608)		$ (16,117)
Ending balance at Dec. 31, 2019	3,586,184	$ 36,943				9,624	1,005	0	44,081		3,658,197	$ 36,943			(126,723)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	491,723										491,723
Other comprehensive income (loss), net of tax	138,986														138,986
Issuance of preferred stock	$ 339,937							339,937
Stock repurchases during period			333,755			813				$ 44,081			288,861
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2016-13 [Member]
Cash dividends			(15,010)	$ (1,678)		0	0		0				(15,010)	$ (1,678)	0
Preferred stock dividends declared	$ 14,062										14,062
Ending balance at Dec. 31, 2020	4,229,268				$ 1,005	8,811		339,937	0		3,867,252				12,263
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	547,459										547,459
Other comprehensive income (loss), net of tax	(2,487)														(2,487)
Cash dividends			$ (16,565)	$ (1,890)									$ (16,565)	$ (1,890)
Preferred stock dividends declared	18,544										18,544
Ending balance at Dec. 31, 2021	$ 4,737,241					$ 8,811	$ 1,005	$ 339,937	$ 0		$ 4,377,712				$ 9,776