Pension Benefits, Other Postretirement Benefits and Employee Savings and Investment Plans (Amounts Recognized in Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Non-current assets	$ 12,790	$ 19,273
Pension Benefits
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Non-current assets	12,790	19,273
Current liabilities	(5)	(4)
Non-current liabilities	(250)	(225)
Accumulated other comprehensive (loss) income	12,535	19,044
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Net actuarial (loss) gain	(13,085)	(59,972)
Prior service benefit	0	0
Accumulated other comprehensive (loss) income	(13,085)	(59,972)
Other Postretirement Benefits
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Non-current assets	0	0
Current liabilities	(282)	(334)
Non-current liabilities	(1,317)	(1,469)
Accumulated other comprehensive (loss) income	(1,599)	(1,803)
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Net actuarial (loss) gain	54	68
Prior service benefit	209	1,220
Accumulated other comprehensive (loss) income	$ 263	$ 1,288