Pensions and Other Postretirement Benefit Plans (Schedule of Net Periodic Benefit Plan Cost) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 355	$ 545
Interest cost	1,417	1,338
Expected return on assets	(1,706)	(1,606)
Amortization of prior service cost/(credit)	(1)	3
Amortization of net actuarial loss	500	544
Net periodic benefit cost	565	824
Other postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	29	33
Interest cost	305	276
Expected return on assets	0	0
Amortization of prior service cost/(credit)	(1,122)	(1,122)
Amortization of net actuarial loss	471	565
Net periodic benefit cost	$ (317)	$ (248)