Segment Information - Additional Segment Information - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Operating revenues	$ 194,960	$ 148,917	$ 545,261	$ 464,863
Cost of gas	79,720	41,193	225,308	153,403
Environmental remediation	2,267	1,509	6,970	5,286
Operating Segments [Member] | Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Natural Gas Distribution revenues	179,727	134,849	516,214	431,402
Other regulated services	4,907	4,765	9,818	9,550
Operating revenues	184,634	139,614	526,032	440,952
Cost of gas	79,776	41,249	225,420	153,515
Environmental remediation	2,272	1,509	6,970	5,286
Revenue taxes	8,208	5,650	21,532	18,305
NGD margin	$ 94,378	$ 91,206	$ 272,110	$ 263,846