Benefit Plans (Schedule of Net Benefit Costs Details) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Pension Plan, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	$ 198	$ 207
Defined Benefit Plan, Interest Cost	3,649	3,517
Defined Benefit Plan, Expected Return on Plan Assets	(3,788)	(3,902)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	75	570
Defined Benefit Plan, Amortization of Gains (Losses)	830	1,057
Defined Benefit Plan, Net Periodic Benefit Cost	964	1,449
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	26	41
Defined Benefit Plan, Interest Cost	64	144
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(636)	(160)
Defined Benefit Plan, Amortization of Gains (Losses)	245	81
Defined Benefit Plan, Net Periodic Benefit Cost	$ (301)	$ 106