Pension and Other Postretirement Plans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Defined Benefit Plan Deferred Pension And Other Postretirement Benefit Plan Costs Recovered [Abstract]
Deferred (recognized) pension and OPEB costs	$ (600)	$ (1,400)
Amortization of:
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Amortization of Prior Service Cost (Credit), Statement of Income or Comprehensive Income [Extensible Enumeration]	Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Transition Asset (Obligation), Statement of Income or Comprehensive Income [Extensible Enumeration]	Nonoperating Income (Expense)
Pension Benefits [Member]
Components of net periodic benefit cost:
Service cost	$ 651	759
Interest cost	4,256	4,244
Expected return on assets	(7,261)	(7,151)
Amortization of:
Actuarial (gain) loss	48	116
Net periodic benefit (credit) cost	(2,306)	(2,032)
Postretirement Benefits [Member]
Components of net periodic benefit cost:
Service cost	183	211
Interest cost	760	797
Expected return on assets	(724)	(691)
Amortization of:
Transition obligation	1	1
Prior service credit	0	(4)
Actuarial (gain) loss	(148)	(77)
Net periodic benefit (credit) cost	$ 72	$ 237