Segment Information - Additional Segment Information - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Operating revenues	$ 237,859	$ 194,960	$ 700,282	$ 545,261
Cost of gas	102,433	79,720	308,182	225,308
Environmental remediation	2,140	2,267	7,515	6,970
Operating Segments [Member] | Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Natural Gas Distribution revenues	218,988	179,727	662,049	516,214
Other regulated services	4,726	4,907	9,435	9,818
Operating revenues	223,714	184,634	671,484	526,032
Cost of gas	102,490	79,776	308,295	225,420
Environmental remediation	2,140	2,272	7,515	6,970
Revenue taxes	9,159	8,208	28,134	21,532
NGD margin	$ 109,925	$ 94,378	$ 327,540	$ 272,110