Segment Information - Additional Segment Information - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Operating revenues	$ 116,839	$ 101,447	$ 662,100	$ 566,310
Cost of gas	36,105	25,266	261,413	178,669
Environmental remediation	980	806	7,950	6,092
Operating Segments [Member] | Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Natural Gas Distribution revenues	98,391	86,271	614,605	517,673
Other regulated services	4,904	4,771	14,722	14,321
Operating revenues	103,295	91,042	629,327	531,994
Cost of gas	36,258	25,322	261,678	178,837
Environmental remediation	975	806	7,945	6,092
Revenue taxes	4,375	3,838	25,907	22,143
NGD margin	$ 61,687	$ 61,076	$ 333,797	$ 324,922