Segment Information - Additional Segment Information - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Operating revenues	$ 211,714	$ 237,859	$ 645,184	$ 700,282
Cost of gas	72,970	102,433	248,687	308,182
Environmental remediation	2,329	2,140	8,075	7,515
Operating Segments [Member] \| Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Natural Gas Distribution revenues	189,979	218,988	602,966	662,049
Other regulated services	4,883	4,726	9,760	9,435
Operating revenues	194,862	223,714	612,726	671,484
Cost of gas	73,026	102,490	248,799	308,295
Environmental remediation	2,329	2,140	8,075	7,515
Revenue taxes	9,198	9,159	27,393	28,134
NGD margin	$ 110,309	$ 109,925	$ 328,459	$ 327,540

Amount, before recovery, of expense for known and estimated future costs arising from requirement to perform environmental remediation.

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