Employee and Retiree Benefit Plans (Amounts Included in Accumulated Other Comprehensive Income Expected to be Amortized into Net Periodic Benefit Expense) (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ (14,117)
Prior service (cost) credit	(956)
Amounts included in accumulated other comprehensive loss expected to be amortized into net periodic benefit expense	(15,073)
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	(391)
Amounts included in accumulated other comprehensive loss expected to be amortized into net periodic benefit expense	$ (391)