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, 2022	$ 36,796	$ 1,149,899	$ 2,197,918	$ (2,588,145)	$ 2,247	$ 798,715
Net income			107,498			107,498
Dividends paid			(11,412)			(11,412)
Stock awards and exercise of stock options	200	89,995		(20,014)		70,181
Purchases of treasury stock				(13,425)		(13,425)
Other		521		(73)	74	522
Balance at Jun. 30, 2023	36,996	1,240,415	2,294,004	(2,621,657)	2,321	952,079
Balance at Mar. 31, 2023	36,884	1,186,119	2,246,354	(2,591,588)	2,284	880,053
Net income			53,377			53,377
Dividends paid			(5,727)			(5,727)
Stock awards and exercise of stock options	112	53,657		(16,608)		37,161
Purchases of treasury stock				(13,425)		(13,425)
Other		639		(36)	37	640
Balance at Jun. 30, 2023	36,996	1,240,415	2,294,004	(2,621,657)	2,321	952,079
Balance at Dec. 31, 2023	37,184	1,341,273	2,446,925	(2,719,588)	2,082	1,107,876
Net income			135,904			135,904
Dividends paid			(12,107)			(12,107)
Stock awards and exercise of stock options	129	75,667		(11,286)		64,510
Purchases of treasury stock				(88,113)		(88,113)
Other		(774)		(66)	67	(773)
Balance at Jun. 30, 2024	37,313	1,416,166	2,570,722	(2,819,053)	2,149	1,207,297
Balance at Mar. 31, 2024	37,297	1,398,733	2,505,892	(2,760,543)	2,116	1,183,495
Net income			70,887			70,887
Dividends paid			(6,057)			(6,057)
Stock awards and exercise of stock options	16	17,555		(2,709)		14,862
Purchases of treasury stock				(55,769)		(55,769)
Other		(122)		(32)	33	(121)
Balance at Jun. 30, 2024	$ 37,313	$ 1,416,166	$ 2,570,722	$ (2,819,053)	$ 2,149	$ 1,207,297