Segment Information - Additional Segment Information - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Operating revenues	$ 141,479	$ 116,839	$ 841,761	$ 662,100
Cost of gas	49,180	36,105	357,362	261,413
Environmental remediation	1,032	980	8,547	7,950
Operating Segments [Member] | Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Natural Gas Distribution revenues	119,892	98,391	781,941	614,605
Other regulated services	4,732	4,904	14,167	14,722
Operating revenues	124,624	103,295	796,108	629,327
Cost of gas	49,235	36,258	357,530	261,678
Environmental remediation	1,032	975	8,547	7,945
Revenue taxes	5,425	4,375	33,559	25,907
NGD margin	$ 68,932	$ 61,687	$ 396,472	$ 333,797