Consolidated Statements Of Equity - USD ($) $ in Thousands	Common Stock [Member]	Capital In Excess Of Par Value [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2020	$ 124,285	$ 3,379,057	$ 1,261,862	$ (81,327)	$ 4,683,877
Net income			431,612		431,612
Dividends declared and paid			(258,650)		(258,650)
Issuance of common stock from stock purchase contracts	64	(64)
Issuance of common stock under dividend reinvestment plan	187	16,612			16,799
Issuance of common stock from at-the-market sale agreements	3,350	296,389			299,739
Repurchase of stock				(3,291)	(3,291)
Equity compensation plan	103	(103)
Exercise of stock options	61	4,111			4,172
Stock-based compensation		9,998	(623)		9,375
Other		(186)		1,003	817
Balance at Dec. 31, 2021	128,050	3,705,814	1,434,201	(83,615)	5,184,450
Net income			465,237		465,237
Dividends declared and paid			(288,632)		(288,632)
Dividends declared			(75,808)		(75,808)
Issuance of common stock from stock purchase contracts	4,515	(4,515)
Issuance of common stock under dividend reinvestment plan	184	16,435			16,619
Issuance of common stock from at-the-market sale agreements	661	62,379			63,040
Repurchase of stock				(1,192)	(1,192)
Equity compensation plan	41	(41)
Exercise of stock options	35	2,440			2,475
Stock-based compensation		12,094	(667)		11,427
Other		(1,344)		1,114	(230)
Balance at Dec. 31, 2022	133,486	3,793,262	1,534,331	(83,693)	5,377,386
Net income			498,226		498,226
Dividends declared and paid			(240,999)		(240,999)
Dividends declared			(83,929)		(83,929)
Issuance of common stock under dividend reinvestment plan	215	15,790			16,005
Issuance of common stock from at-the-market sale agreements	4,470	318,513			322,983
Repurchase of stock				(3,981)	(3,981)
Equity compensation plan	122	(122)
Exercise of stock options	4	283			287
Stock-based compensation		11,330	(954)		10,376
Other		(1,360)		1,189	(171)
Balance at Dec. 31, 2023	$ 138,297	$ 4,137,696	$ 1,706,675	$ (86,485)	$ 5,896,183