Benefit Plans (Schedule of Net Benefit Costs Details) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Pension Plan, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	$ 207	$ 182	$ 415	$ 364
Defined Benefit Plan, Interest Cost	3,517	3,584	7,035	7,168
Defined Benefit Plan, Expected Return on Plan Assets	(3,902)	(4,009)	(7,804)	(8,017)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	570	698	1,140	1,331
Defined Benefit Plan, Amortization of Gains (Losses)	1,057	804	2,113	1,513
Defined Benefit Plan, Net Periodic Benefit Cost	1,449	1,259	2,899	2,359
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	41	16	83	33
Defined Benefit Plan, Interest Cost	144	164	288	327
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(160)	(117)	(319)	(234)
Defined Benefit Plan, Amortization of Gains (Losses)	81	59	163	118
Defined Benefit Plan, Net Periodic Benefit Cost	$ 106	$ 122	$ 215	$ 244