Pension and Other Postretirement Benefits - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 107	$ 174	$ 211	$ 354
Interest cost	2,511	1,317	4,973	2,677
Expected return on plan assets	(2,026)	(2,012)	(4,023)	(4,097)
Actuarial loss (gain) amortization	103	248	205	505
Prior service cost (income) amortization	0	2	0	5
Net periodic benefit cost (income)	695	(271)	1,366	(556)
Other Postretirement Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	0	8	0	0
Interest cost	19	2	38	11
Expected return on plan assets	0	0	0	0
Actuarial loss (gain) amortization	(30)	(23)	(60)	(47)
Prior service cost (income) amortization	(4)	(9)	(8)	(8)
Net periodic benefit cost (income)	$ (15)	$ (22)	$ (30)	$ (44)