Pensions and Other Postretirement Benefits (Accrued Pension and Other Postretirement Costs) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Accrued pension and other postretirement costs	$ (15,669)	$ (14,982)
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Accrued pension and other postretirement costs	(10,851)	(9,421)
OPEB Plans
Defined Benefit Plan Disclosure [Line Items]
Accrued pension and other postretirement costs	$ (4,633)	$ (4,645)