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, 2021	128,050	3,705,814	1,434,201	(83,615)	5,184,450
Net income					350,305
Balance at Sep. 30, 2022	132,764	3,723,523	1,570,652	(83,837)	5,343,102
Balance at Mar. 31, 2022	128,140	3,713,560	1,497,757	(84,357)	5,255,100
Net income			82,291		82,291
Dividends declared and paid			(2,424)		(2,424)
Issuance of common stock from stock purchase contracts	4,515	(4,515)
Issuance of common stock under dividend reinvestment plan	47	4,007			4,054
Repurchase of stock				(15)	(15)
Equity compensation plan	2	(2)
Exercise of stock options	3	224			227
Stock-based compensation		2,725	(182)		2,543
Other		(24)		280	256
Balance at Jun. 30, 2022	132,707	3,715,975	1,577,442	(84,092)	5,342,032
Net income			68,638		68,638
Dividends declared and paid			(75,246)		(75,246)
Issuance of common stock under dividend reinvestment plan	44	4,206			4,250
Repurchase of stock				(29)	(29)
Equity compensation plan	3	(3)
Exercise of stock options	10	660			670
Stock-based compensation		2,702	(182)		2,520
Other		(17)		284	267
Balance at Sep. 30, 2022	132,764	3,723,523	1,570,652	(83,837)	5,343,102
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
Balance at Dec. 31, 2022	133,486	3,793,262	1,534,331	(83,693)	5,377,386
Net income					362,778
Balance at Sep. 30, 2023	138,235	4,131,834	1,739,271	(86,783)	5,922,557
Balance at Mar. 31, 2023	133,848	3,819,804	1,649,621	(87,331)	5,515,942
Net income			91,268		91,268
Dividends declared and paid			(1)		(1)
Issuance of common stock under dividend reinvestment plan	51	3,901			3,952
Repurchase of stock				(42)	(42)
Equity compensation plan	9	(9)
Exercise of stock options	1	105			106
Stock-based compensation		3,515	(206)		3,309
Other		(117)		281	164
Balance at Jun. 30, 2023	133,909	3,827,199	1,740,682	(87,092)	5,614,698
Net income			80,076		80,076
Dividends declared and paid			(81,230)		(81,230)
Issuance of common stock under dividend reinvestment plan	56	3,936			3,992
Issuance of common stock from at-the-market sale agreements	4,270	299,419			303,689
Repurchase of stock				(2)	(2)
Exercise of stock options		20			20
Stock-based compensation		1,967	(257)		1,710
Other		(707)		311	(396)
Balance at Sep. 30, 2023	$ 138,235	$ 4,131,834	$ 1,739,271	$ (86,783)	$ 5,922,557