Employee and Retiree Benefit Plans (Amounts Included in Accumulated Other Comprehensive Income Expected to be Amortized into Net Periodic Benefit Expense) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ (14,527)
Prior service (cost) credit	(1,295)
Amounts included in accumulated other comprehensive loss expected to be amortized into net periodic benefit cost	(15,822)
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	(155)
Prior service (cost) credit	82
Amounts included in accumulated other comprehensive loss expected to be amortized into net periodic benefit cost	$ (73)