Convertible Debt (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2014	Dec. 31, 2013
Debt Disclosure [Abstract]
Debt Conversion			$ 61,100,000
Debt Instrument, Face Amount						400,000,000
Schedule of Available-for-sale Securities [Line Items]
Repayments of Convertible Debt			61,125,000	0
Issuance of Common Stock in connection with conversion of convertible senior notes (in shares)			521,876
Gains (Losses) on Extinguishment of Debt	(10,787,000)	0	(10,787,000)	0
Stock Issued During Period, Shares, Acquisitions			521,876
Payments for Repurchase of Warrants			143,041,000	0
Maximum number of shares issuable upon exercise of warrants	4,033,324		4,033,324		4,760,840
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt, Subsequent Adjustments			$ (156,651,000)