STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Regulated Operating Revenue	$ 379,125	$ 340,398	$ 1,738,056	$ 1,452,855
Cost of natural gas	76,614	59,632	707,018	514,593
Operating expenses
Operations and maintenance	137,198	130,743	403,480	385,403
Depreciation and amortization	76,933	72,126	237,951	221,247
General taxes	22,999	18,448	71,872	57,023
Total operating expenses	237,130	221,317	713,303	663,673
Operating income	65,381	59,449	317,735	274,589
Other Nonoperating Income (Expense)	2,363	2,982	5,453	7,467
Interest expense, net	(35,373)	(39,148)	(106,349)	(107,475)
Income before income taxes	32,371	23,283	216,839	174,581
Income taxes	(5,905)	(4,015)	(38,921)	(28,753)
Net income	$ 26,466	$ 19,268	$ 177,918	$ 145,828
Earnings per share
Basic	$ 0.44	$ 0.34	$ 2.96	$ 2.57
Diluted	$ 0.44	$ 0.34	$ 2.94	$ 2.56
Weighted Average Number of Shares Outstanding, Basic [Abstract]
Basic	60,183	56,825	60,125	56,768
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Diluted	60,554	57,093	60,425	56,906
Common Stock, Dividends, Per Share, Declared	$ 0.67	$ 0.66	$ 2.01	$ 1.98