Pension and Other Postretirement Benefits - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 109	$ 104
Interest cost	2,375	2,455
Expected return on plan assets	(2,030)	(1,997)
Actuarial loss (gain) amortization	127	101
Prior service cost (income) amortization	7	8
Net periodic benefit cost (income)	588	671
Other Postretirement Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	0	0
Interest cost	15	19
Expected return on plan assets	0	0
Actuarial loss (gain) amortization	(29)	(30)
Prior service cost (income) amortization	0	(4)
Net periodic benefit cost (income)	$ (14)	$ (15)