Goodwill and Other Intangible Assets - Narrative (Details)	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Goodwill [Line Items]
Goodwill	$ 488,960,000	$ 488,960,000
Goodwill, impairment loss	0	0	$ 0
Amortization of intangible assets	2,100,000	2,200,000	$ 2,500,000
Natural gas distribution
Goodwill [Line Items]
Goodwill	$ 345,700,000	$ 345,700,000
Percentage of fair value in excess of carrying amount	4.00%
Risk adjusted cost of capital, percentage	0.067	0.064
Construction services
Goodwill [Line Items]
Goodwill	$ 143,200,000	$ 143,200,000