Pension, Other Postretirement Benefits and Employee Savings and Investment Plans (Amounts Recognized in Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Noncurrent assets	$ 19,273	$ 3,021
Current liabilities	(4)	(5)
Noncurrent liabilities	(225)	(8,720)
Net amount recognized at end of year	19,044	(5,704)
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Net actuarial (loss) gain	(59,972)	(59,645)
Prior service benefit	0	0
Net amount recognized at end of year	(59,972)	(59,645)
Retirement Health and Life Insurance Benefits
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Noncurrent assets	0	0
Current liabilities	(334)	(352)
Noncurrent liabilities	(1,469)	(1,685)
Net amount recognized at end of year	(1,803)	(2,037)
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Net actuarial (loss) gain	68	63
Prior service benefit	1,220	2,821
Net amount recognized at end of year	$ 1,288	$ 2,884