Nonpension Postretirement Benefits (Amounts Recognized in Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Current liability	$ 4,903	$ 4,800
Long-term liability	55,282	63,301
Nonpension Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Current liability	4,903	4,800
Long-term liability	55,282	63,301
Total accrued postretirement benefit liability	$ 60,185	$ 68,101