Pensions and Other Postretirement Benefit Plans (Schedule of Net Periodic Benefit Plan Cost) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 565	$ 708
Interest cost	2,141	2,828
Expected return on assets	(1,955)	(3,405)
Amortization of prior service cost/(income)	(16)	(1)
Amortization of net actuarial loss	279	997
Net periodic benefit cost/(income)	1,014	1,127
Other postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	30	57
Interest cost	937	611
Expected return on assets	0	0
Amortization of prior service cost/(income)	(2,045)	(2,244)
Amortization of net actuarial loss	414	941
Net periodic benefit cost/(income)	$ (664)	$ (635)