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	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amortization of net prior service cost	$ (140)	$ (140)
Amortization of net loss	881	1,372
Adjustment due to effects of regulation	(752)	(1,255)
Other comprehensive (income) loss, defined benefit plan, reclassification adjustment from AOCI, before tax	(11)	(23)
Other comprehensive (income) loss, defined benefit plan, reclassification adjustment from AOCI, tax	2	5
Other comprehensive (income) loss, defined benefit plan, reclassification adjustment from AOCI, after tax	$ (9)	$ (18)