Pensions and Other Postretirement Benefit Plans (Schedule of Net Periodic Benefit Plan Cost) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 708	$ 1,090
Interest cost	2,828	2,674
Expected return on assets	(3,405)	(3,211)
Amortization of prior service cost/(credit)	(1)	7
Amortization of net actuarial loss	997	1,087
Net periodic benefit cost	1,127	1,647
Other postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	57	66
Interest cost	611	551
Expected return on assets	0	0
Amortization of prior service cost/(credit)	(2,244)	(2,244)
Amortization of net actuarial loss	941	1,130
Net periodic benefit cost	$ (635)	$ (497)