Pension and Other Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Pensions
Pension and other postretirement benefits expenses
Service cost	$ 1,328	$ 1,538	$ 2,883	$ 3,279
Interest cost	3,434	3,204	6,868	6,376
Expected return on plan assets	(7,257)	(6,962)	(14,538)	(13,934)
Amortization of prior service cost	99	80	207	165
Amortization of actuarial losses	3,518	4,080	6,657	8,006
Special termination benefits	0	0	136	0
Net periodic benefit cost	1,122	1,940	2,213	3,892
Other Postretirement Benefits
Pension and other postretirement benefits expenses
Service cost	15	25	39	50
Interest cost	203	206	409	412
Amortization of prior service cost	9	8	18	15
Amortization of actuarial losses	(1)	70	(1)	140
Net periodic benefit cost	$ 226	$ 309	$ 465	$ 617