Investments and Fair Value Measurements Fair Value Inputs, Quantitative Information (Details) (Significant Unobservable Inputs (Level 3), Fair Value, Measurements, Recurring [Member], USD $) In Thousands, except Per Share data, unless otherwise specified							3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Option Model [Member]	Dec. 31, 2013 Option Model [Member]	Mar. 31, 2014 Discounted Cash Flow [Member]	Dec. 31, 2013 Discounted Cash Flow [Member]	Mar. 31, 2014 Warrants Option Model [Member] years	Mar. 31, 2013 Warrants Option Model [Member] years	Mar. 31, 2014 Derivative Financial Instruments, Liabilities [Member] Discounted Cash Flow [Member]	Mar. 31, 2013 Derivative Financial Instruments, Liabilities [Member] Discounted Cash Flow [Member]	Mar. 31, 2014 Minimum [Member] Derivative Financial Instruments, Liabilities [Member] Discounted Cash Flow [Member]	Mar. 31, 2013 Minimum [Member] Derivative Financial Instruments, Liabilities [Member] Discounted Cash Flow [Member]	Mar. 31, 2014 Maximum [Member] Derivative Financial Instruments, Liabilities [Member] Discounted Cash Flow [Member]	Mar. 31, 2013 Maximum [Member] Derivative Financial Instruments, Liabilities [Member] Discounted Cash Flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Warrants	$ 1,602	$ 1,935	$ 1,602	$ 1,935
Stock price (dollars per share)							$ 3.02	$ 3.13	$ 21.54	$ 16.37
Exercise price (dollars per share)							$ 1.68	$ 1.68
Term (in years)							2.6	2.8
Volatility							50.64%	53.82%	16.00%	18.00%
Dividend rate							0.00%	0.00%
Risk-free return							0.70%	0.72%
Fair value of derivatives embedded within convertible debt	$ 193,975	$ 112,062			$ 193,975	$ 112,062
Assumed annual stock dividend									5.00%	5.00%
Assumed annual cash dividend (dollars per share)									$ 1.60	$ 1.60
Convertible trading price									104.56%	118.70%
Implied credit spread									6.75%	8.00%	6.25%	7.50%	7.25%	8.50%