Debt Obligations (Term Loan Facilities) (Details) In Millions, unless otherwise specified	0 Months Ended	3 Months Ended			0 Months Ended
	Jan. 24, 2014 Term Loan Facility [Member] USD ($)	Mar. 31, 2014 Term Loan Facility [Member] USD ($)	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] Term Loan Facility [Member]	Jan. 24, 2014 London Interbank Offered Rate (LIBOR) [Member] Combined Procurement Agreement [Member]	Jan. 24, 2014 Minimum [Member] Term Loan Facility [Member]	Jan. 24, 2014 Maximum [Member] Term Loan Facility [Member]	Mar. 31, 2014 Convertible Senior Notes, 5.5% Fixed Rate, Due 2016 [Member]	Dec. 31, 2013 Convertible Senior Notes, 5.5% Fixed Rate, Due 2016 [Member]	Mar. 31, 2014 11.5% Convertible Bonds [Member]
Line of Credit Facility [Line Items]
Credit facility initiation date		Jan. 24, 2014
Maximum credit amount	$ 255.0		$ 130.0	£ 78.0
Amount of term loan facility advanced	125		130
Prepayment fee and accrued interest	2.0
(Loss) on early extinguishment of debt		$ 3.5
Basis spread on variable rate					7.00%	7.00%
Interest rate						1.25%	1.25%		5.50%	5.50%	11.50%
Maturity date		Nov. 30, 2017
Minimum interest coverage ratio							150.00%
Leverage ratio								500.00%
Asset coverage ratio							200.00%