Pensions and Other Post-retirement Benefits - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2,013	$ 2,013	$ 6,039	$ 6,014
Interest cost	5,782	5,999	17,346	17,912
Expected return on plan assets	(12,418)	(12,005)	(37,254)	(36,015)
Amortization of prior service cost	40	32	120	96
Recognized net actuarial losses	205	197	615	591
Settlements			0	721
Net periodic benefit (income) cost	(4,378)	(3,764)	(13,134)	(10,681)
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	21	31	63	93
Interest cost	228	276	684	828
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	0	0	0	0
Recognized net actuarial losses	127	163	381	489
Settlements			0	0
Net periodic benefit (income) cost	$ 376	$ 470	$ 1,128	$ 1,410