Commitments And Contingencies (Combined Procurement Agreement) (Details)			0 Months Ended				0 Months Ended
	Jan. 24, 2014 USD ($)	Sep. 30, 2012 USD ($)	Sep. 30, 2014 Combined Procurement Agreement [Member] USD ($)	Dec. 31, 2014 Combined Procurement Agreement [Member] USD ($)	Jan. 24, 2014 Combined Procurement Agreement [Member] USD ($)	Jan. 24, 2014 Combined Procurement Agreement [Member] GBP (£)	Jan. 24, 2014 London Interbank Offered Rate (LIBOR) [Member] Combined Procurement Agreement [Member]	Jan. 24, 2014 London Interbank Offered Rate (LIBOR) [Member] Combined Procurement Agreement [Member]
Commitments And Contingencies [Line Items]
Maximum credit amount	$ 255,000,000	$ 125,000,000			$ 130,000,000	£ 78,000,000
Amount outstanding				90,000,000
Basis spread on variable rate							7.00%
Interest rate								1.25%
Repayment of outstanding interest			1,900,000
Repayment of outstanding fees			$ 2,400,000