Pension and Other Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Pensions
Pension and other postretirement benefits expenses
Service cost	$ 1,555	$ 1,741
Interest cost	3,434	3,172
Expected return on plan assets	(7,281)	(6,972)
Amortization of prior service cost	108	85
Amortization of actuarial losses	3,139	3,926
Special termination benefits	136	0
Net periodic benefit cost	1,091	1,952
Other Postretirement Benefits
Pension and other postretirement benefits expenses
Service cost	24	25
Interest cost	206	206
Amortization of prior service cost	0	7
Amortization of actuarial losses	9	70
Net periodic benefit cost	$ 239	$ 308