Retirement Benefits (Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Amortization of:
Net actuarial (gain) loss		$ (2,221)	$ 6,795
Net actuarial loss		(8,143)	(2,197)
Prior service costs		(3,023)	(3,023)
Total recognized in other comprehensive income	(10,232)	(13,387)	1,575
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net after tax unamortized periodic pension cost	(4,624,134)	(4,369,394)
Net pension asset
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net after tax unamortized periodic pension cost	$ 0	$ 6,651	$ 15,351	$ 14,329