Condensed Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Capital In Excess Of Par Value [Member]	Retained Earnings [Member]
Balance at Dec. 31, 2019		$ 11,953	$ 218,462	$ 2,850,302
Share repurchases		(223)		(306,568)
Cash dividends declared				(53,475)
Share-based compensation and share issuances		6	8,371
Taxes paid in exchange for shares withheld		(2)	(2,731)
Forward contract (settlements) for accelerated share repurchases			(37,500)
Cash paid for fractional shares		(1)	(611)
Net income				482,850
Balance at Sep. 30, 2020	$ 3,170,833	11,733	185,991	2,973,109
Balance at Jun. 30, 2020		11,734	181,895	2,788,839
Cash dividends declared				(17,598)
Share-based compensation and share issuances		(1)	4,096
Net income				201,868
Balance at Sep. 30, 2020	3,170,833	11,733	185,991	2,973,109
Balance at Dec. 31, 2020	3,326,288	11,706	226,451	3,088,131
Share repurchases		(209)		(536,256)
Cash dividends declared				(69,387)
Share-based compensation and share issuances		6	10,928
Taxes paid in exchange for shares withheld		(2)	(4,539)
Forward contract (settlements) for accelerated share repurchases			(62,500)
Net income				755,569
Balance at Sep. 30, 2021	3,419,898	11,501	170,340	3,238,057
Balance at Jun. 30, 2021		11,581	160,204	3,230,593
Share repurchases		(80)		(256,170)
Cash dividends declared				(23,000)
Share-based compensation and share issuances			3,886
Forward contract (settlements) for accelerated share repurchases			6,250
Net income				286,634
Balance at Sep. 30, 2021	$ 3,419,898	$ 11,501	$ 170,340	$ 3,238,057