STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Regulated Operating Revenue	$ 359,363	$ 273,923	$ 1,759,797	$ 1,214,862
Cost of natural gas	126,197	59,399	954,394	467,169
Operating expenses
Operations and maintenance	113,832	105,732	339,506	320,152
Depreciation and amortization	55,234	51,150	167,414	154,288
General taxes	17,048	15,835	52,105	49,999
Total operating expenses	186,114	172,717	559,025	524,439
Operating income	47,052	41,807	246,378	223,254
Other income (expense), net	793	(1,805)	(7,335)	(1,758)
Interest expense, net	(19,551)	(15,392)	(51,466)	(45,828)
Income before income taxes	28,294	24,610	187,577	175,668
Income taxes	(4,593)	(4,357)	(32,867)	(29,746)
Net income	$ 23,701	$ 20,253	$ 154,710	$ 145,922
Earnings per share
Basic	$ 0.44	$ 0.38	$ 2.86	$ 2.73
Diluted	$ 0.44	$ 0.38	$ 2.85	$ 2.72
Weighted Average Number of Shares Outstanding, Basic [Abstract]
Basic	54,310	53,710	54,164	53,516
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Diluted	54,482	53,793	54,282	53,618
Common Stock, Dividends, Per Share, Declared	$ 0.62	$ 0.58	$ 1.86	$ 1.74