Pensions and Other Postretirement Benefit Plans (Schedule of Net Periodic Benefit Plan Cost) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 281	$ 355
Interest cost	1,063	1,417
Expected return on assets	(971)	(1,706)
Amortization of prior service cost/(credit)	(8)	(1)
Amortization of net actuarial loss	139	500
Net periodic benefit cost/(credit)	504	565
Other postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	15	29
Interest cost	468	305
Expected return on assets	0	0
Amortization of prior service cost/(credit)	(1,023)	(1,122)
Amortization of net actuarial loss	207	471
Net periodic benefit cost/(credit)	$ (333)	$ (317)