Employee and Retiree Benefit Plans (Benefit Payments, Reflected Expected Future Service as Appropriate which are Expected to be Paid in Future Years from Assets of Plans or by Company) (Details) $ in Thousands	Dec. 31, 2015 USD ($)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2016	$ 37,255
2017	37,744
2018	38,649
2019	39,931
2020	40,903
2021-2025	222,198
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2016	6,251
2017	6,445
2018	6,683
2019	6,955
2020	7,246
2021-2025	$ 40,661

Employee and Retiree Benefit Plans (Benefit Payments, Reflected Expected Future Service as Appropriate which are Expected to be Paid in Future Years from Assets of Plans or by Company) (Details)
$ in Thousands

Dec. 31, 2015

USD ($)

Defined Benefit Plan Disclosure [Line Items]

$ 37,255

37,744

38,649

39,931

40,903

222,198