Benefit Plans (Schedule of Net Benefit Costs Details) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Pension Plan, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	$ 207	$ 182
Defined Benefit Plan, Interest Cost	3,517	3,584
Defined Benefit Plan, Expected Return on Plan Assets	(3,902)	(4,009)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	570	634
Defined Benefit Plan, Amortization of Gains (Losses)	1,057	708
Defined Benefit Plan, Net Periodic Benefit Cost	1,449	1,099
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	41	16
Defined Benefit Plan, Interest Cost	144	164
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(160)	(117)
Defined Benefit Plan, Amortization of Gains (Losses)	81	59
Defined Benefit Plan, Net Periodic Benefit Cost	$ 106	$ 122