Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period Of Adoption, Adjusted Balance	Preferred Stock	Preferred Stock Cumulative Effect, Period Of Adoption, Adjusted Balance	Common Stock	Common Stock Cumulative Effect, Period Of Adoption, Adjusted Balance	Additional Paid-In Capital	Additional Paid-In Capital Cumulative Effect, Period Of Adoption, Adjusted Balance	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period Of Adoption, Adjusted Balance	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings Cumulative Effect, Period Of Adoption, Adjusted Balance	Treasury Stock	Treasury Stock Cumulative Effect, Period Of Adoption, Adjusted Balance
Beginning balance at Dec. 31, 2020	$ 8,771,092	$ (7,837,571)	$ 933,521	$ 0	$ 0	$ 113,218	$ 113,218	$ 527,435	$ 527,435	$ 3,029,244	$ (7,825,049)	$ (4,795,805)	$ 5,874,109	$ (12,522)	$ 5,861,587	$ (772,914)	$ (772,914)
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)	1,591,871									560,757			1,031,114
Common dividends declared	(80,247)												(80,247)
Acquisition of treasury stock	(541,435)															(541,435)
Stock-based compensation	30,272							12,103								18,169
Exercise of stock options	69,826												(29,398)			99,224
Retirement of treasury stock	0					(4,000)		(18,974)					(327,323)			350,297
Ending balance at Dec. 31, 2021	2,003,808			0		109,218		520,564		(4,235,048)			6,455,733			(846,659)
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)	2,339,121									1,444,735			894,386
Common dividends declared	(80,956)												(80,956)
Acquisition of treasury stock	(454,638)															(454,638)
Stock-based compensation	35,650							29,119					(345)			6,876
Exercise of stock options	106,592												(29,838)			136,430
Retirement of treasury stock	0					(4,000)		(20,022)					(344,445)			368,467
Ending balance at Dec. 31, 2022	3,949,577			0		105,218		529,661		(2,790,313)			6,894,535			(789,524)
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)	988,649									17,894			970,755
Common dividends declared	(85,139)												(85,139)
Acquisition of treasury stock	(511,100)															(511,100)
Stock-based compensation	30,736							18,466								12,270
Exercise of stock options	114,080												(19,395)			133,475
Retirement of treasury stock	0					(3,000)		(15,653)					(281,943)			300,596
Ending balance at Dec. 31, 2023	$ 4,486,803			$ 0		$ 102,218		$ 532,474		$ (2,772,419)			$ 7,478,813			$ (854,283)