Pension and Other Postretirement Benefits Costs - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		4.00%
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate		2029
Payment for Pension and Other Postretirement Benefits		$ 0
Expected future employer contributions		$ 20,600
Pension Plan Withdrawal Liability, Payments		20 years
Regulatory amortization of gas reserves		$ 3,217	$ 5,589	$ 13,897
Forecast [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Regulatory amortization of gas reserves	$ 5,200
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan Assets, Amount		$ 283,443	280,306
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year		6.50%
Non-Qualified Pension Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan Assets, Amount		$ 0
Defined Benefit Plan, Benefit Obligation		32,800	31,800
Qualified Pension Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Accumulated Benefit Obligation		$ 363,500	$ 353,400