Accumulated Other Comprehensive Loss - Reclassification out of Accumulated Other Comprehensive Loss (Details) - Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] - Reclassification out of Accumulated Other Comprehensive Income [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amortization of net prior service cost	$ (4,095)	$ (793)	$ (794)
Amortization of net loss	57,650	38,070	5,586
Adjustment due to effects of regulation	(42,187)	(33,050)	(10,006)
Other comprehensive (income) loss, defined benefit plan, reclassification adjustment from AOCI, before tax	11,368	4,227	(5,214)
Other comprehensive (income) loss, defined benefit plan, reclassification adjustment from AOCI, tax	(2,387)	(888)	1,095
Other comprehensive (income) loss, defined benefit plan, reclassification adjustment from AOCI, after tax	$ 8,981	$ 3,339	$ (4,119)