Pensions and Other Post-retirement Benefits - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2,013	$ 2,315	$ 6,014	$ 6,945
Interest cost	5,999	5,970	17,912	17,910
Expected return on plan assets	(12,005)	(10,812)	(36,015)	(32,436)
Amortization of prior service cost (credit)	32	37	96	111
Recognized net actuarial losses	197	282	591	846
Settlements			721	1,308
Net periodic benefit (income) cost	(3,764)	(2,208)	(10,681)	(5,316)
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	31	44	93	132
Interest cost	276	248	828	744
Expected return on plan assets	0	0	0	0
Amortization of prior service cost (credit)	0	(46)	0	(138)
Recognized net actuarial losses	163	115	489	345
Settlements			0	0
Net periodic benefit (income) cost	$ 470	$ 361	$ 1,410	$ 1,083