Benefit Plans (Schedule of Net Benefit Costs Details) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Pension Plan, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	$ 207	$ 182	$ 622	$ 546
Defined Benefit Plan, Interest Cost	3,517	3,584	10,552	10,753
Defined Benefit Plan, Expected Return on Plan Assets	(3,902)	(4,009)	(11,706)	(12,026)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	570	633	1,709	1,965
Defined Benefit Plan, Amortization of Gains (Losses)	1,057	708	3,169	2,221
Defined Benefit Plan, Net Periodic Benefit Cost	1,449	1,098	4,346	3,459
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	41	16	124	49
Defined Benefit Plan, Interest Cost	144	164	432	491
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(160)	(117)	(479)	(351)
Defined Benefit Plan, Amortization of Gains (Losses)	81	59	245	177
Defined Benefit Plan, Net Periodic Benefit Cost	$ 106	$ 122	$ 322	$ 366