Regulatory Assets and Liabilities - Regulatory Liabilities (Details-2) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Regulatory Liability [Line Items]
Regulatory Liability	$ 168,913	$ 163,663
Deferred Pension And Other Postretirement Costs [Member]
Regulatory Liability [Line Items]
Regulatory Liability	5,454	8,112
Elm Road [Member]
Regulatory Liability [Line Items]
Regulatory Liability	1,092	0
Income Taxes
Regulatory Liability [Line Items]
Regulatory Liability	109,112	110,817
Non Asset Retirement Obligation Removal Cost [Member]
Regulatory Liability [Line Items]
Regulatory Liability	31,664	29,694
Pension and Other Postretirement Plans Costs [Member]
Regulatory Liability [Line Items]
Regulatory Liability	16,160	11,451
Purchased Gas Adjustment [Member]
Regulatory Liability [Line Items]
Regulatory Liability	4,857	1,448
Other Regulatory Liability [Member]
Regulatory Liability [Line Items]
Regulatory Liability	$ 574	$ 2,141