Nonpension Postretirement Benefits (Amounts Recognized in Balance Sheet) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Current liability	$ 4,800	$ 4,758
Long-term liability	63,301	59,065
Nonpension Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Current liability	4,800	4,758
Long-term liability	63,301	59,065
Total accrued postretirement benefit liability	$ 68,101	$ 63,823