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, 2021	$ 128,050	$ 3,705,814	$ 1,434,201	$ (83,615)	$ 5,184,450
Net income			199,376		199,376
Dividends declared and paid			(67,821)		(67,821)
Dividends declared			(67,863)		(67,863)
Issuance of common stock under dividend reinvestment plan	47	4,070			4,117
Repurchase of stock				(1,012)	(1,012)
Equity compensation plan	29	(29)
Exercise of stock options	14	998			1,012
Stock-based compensation		2,716	(136)		2,580
Other		(9)		270	261
Balance at Mar. 31, 2022	128,140	3,713,560	1,497,757	(84,357)	5,255,100
Balance at Dec. 31, 2022	133,486	3,793,262	1,534,331	(83,693)	5,377,386
Net income			191,434		191,434
Dividends declared and paid			(1)		(1)
Dividends declared			(75,876)		(75,876)
Issuance of common stock under dividend reinvestment plan	49	4,068			4,117
Issuance of common stock from at-the-market sale agreements	200	19,094			19,294
Repurchase of stock				(3,911)	(3,911)
Equity compensation plan	111	(111)
Exercise of stock options	2	101			103
Stock-based compensation		3,410	(267)		3,143
Other		(20)		273	253
Balance at Mar. 31, 2023	$ 133,848	$ 3,819,804	$ 1,649,621	$ (87,331)	$ 5,515,942