Summary of Significant Accounting Policies - Other Expense (Income) - Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Interest income	$ 5,949	$ 1,957	$ 1,943
Interest on regulatory deferrals	8,713	1,914	1,206
Equity-related AFUDC	6,886	6,704	7,004
Non-service portion of pension and other postretirement benefit expenses	630	3,037	(1,386)
Earnings (losses) on investments	(3,227)	48,492	21,402
Other income	575	613	3,129
Total	$ 19,526	$ 62,717	$ 33,298