Consolidated Statements Of Changes In Stockholders' Equity - USD ($) $ in Thousands	Capital Stock [Member]	Paid-In Capital [Member]	Retained Earnings [Member]	Treasury Stock-At Cost [Member]	Deferred Compensation Payable In Company Stock [Member]	Total
Balance at Dec. 31, 2020	$ 36,259	$ 961,404	$ 1,723,777	$ (1,822,579)	$ 2,339	$ 901,200
Net income			268,550			268,550
Dividends paid			(22,016)			(22,016)
Stock awards and exercise of stock options (Note 4)	255	82,921		(31,037)		52,139
Purchases of treasury stock (Note 19)				(576,483)		(576,483)
Other		16		5	(138)	(117)
Balance at Dec. 31, 2021	36,514	1,044,341	1,970,311	(2,430,094)	2,201	623,273
Net income			249,624			249,624
Dividends paid			(22,017)			(22,017)
Stock awards and exercise of stock options (Note 4)	282	106,619		(43,932)		62,969
Purchases of treasury stock (Note 19)				(114,074)		(114,074)
Other		(1,061)		(45)	46	(1,060)
Balance at Dec. 31, 2022	36,796	1,149,899	2,197,918	(2,588,145)	2,247	798,715
Net income			272,509			272,509
Dividends paid			(23,502)			(23,502)
Stock awards and exercise of stock options (Note 4)	388	190,835		(57,796)		133,427
Purchases of treasury stock (Note 19)				(73,813)		(73,813)
Other		539		166	(165)	540
Balance at Dec. 31, 2023	$ 37,184	$ 1,341,273	$ 2,446,925	$ (2,719,588)	$ 2,082	$ 1,107,876