Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock
Beginning 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)	645,526				408,042	237,484
Common dividends declared	(20,543)					(20,543)
Acquisition of treasury stock	(119,482)						(119,482)
Stock-based compensation	9,035			2,504		(345)	6,876
Exercise of stock options	25,931					(9,964)	35,895
Ending balance at Mar. 31, 2022	2,544,275	0	109,218	523,068	(3,827,006)	6,662,365	(923,370)
Beginning 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)	1,468,480
Ending balance at Jun. 30, 2022	3,220,303	0	109,218	531,516	(3,228,025)	6,863,681	(1,056,087)
Beginning balance at Mar. 31, 2022	2,544,275	0	109,218	523,068	(3,827,006)	6,662,365	(923,370)
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)	822,954				598,981	223,973
Common dividends declared	(20,238)					(20,238)
Acquisition of treasury stock	(143,939)						(143,939)
Stock-based compensation	8,448			8,448			0
Exercise of stock options	8,803					(2,419)	11,222
Ending balance at Jun. 30, 2022	3,220,303	0	109,218	531,516	(3,228,025)	6,863,681	(1,056,087)
Beginning 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)	52,830				(170,780)	223,610
Common dividends declared	(21,542)					(21,542)
Acquisition of treasury stock	(179,276)						(179,276)
Stock-based compensation	7,678			(1,022)			8,700
Exercise of stock options	37,024					(4,059)	41,083
Ending balance at Mar. 31, 2023	3,846,291	0	105,218	528,639	(2,961,093)	7,092,544	(919,017)
Beginning 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)	285,286
Ending balance at Jun. 30, 2023	3,980,306	0	105,218	536,126	(2,943,897)	7,285,809	(1,002,950)
Beginning balance at Mar. 31, 2023	3,846,291	0	105,218	528,639	(2,961,093)	7,092,544	(919,017)
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)	232,456				17,196	215,260
Common dividends declared	(21,330)					(21,330)
Acquisition of treasury stock	(89,755)						(89,755)
Stock-based compensation	7,487			7,487
Exercise of stock options	5,157					(665)	5,822
Ending balance at Jun. 30, 2023	$ 3,980,306	$ 0	$ 105,218	$ 536,126	$ (2,943,897)	$ 7,285,809	$ (1,002,950)