Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Consolidated Statements Of Operations [Abstract]
Operating revenues	$ 699,275	$ 583,565
Operating expenses:
Operations and maintenance	142,581	125,075
Purchased gas	227,712	132,153
Depreciation	77,878	71,637
Amortization	468	1,307
Taxes other than income taxes	23,007	21,041
Total operating expenses	471,646	351,213
Operating income	227,629	232,352
Other expense (income):
Interest expense	53,636	50,769
Interest income	(609)	(387)
Allowance for funds used during construction	(5,839)	(2,934)
Gain on sale of other assets		(80)
Other	(1,702)	(3,471)
Income before income taxes	182,143	188,455
Provision for income taxes (benefit)	(17,233)	4,766
Net income	199,376	183,689
Comprehensive income	$ 199,376	$ 183,689
Net income per common share:
Basic	$ 0.76	$ 0.72
Diluted	$ 0.76	$ 0.72
Average common shares outstanding during the period:
Basic	261,952	254,565
Diluted	262,431	254,969