Investments and Fair Value Measurements Fair Value Inputs, Quantitative Information (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 years	Dec. 31, 2012 years
Fair Value Inputs, Assets And Liabilities, Quantitative Information [Line Items]
Warrants	$ 1,935	$ 769
Fair value of derivatives embedded within convertible debt	112,062	172,128
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Assets And Liabilities, Quantitative Information [Line Items]
Warrants	1,935	769
Fair value of derivatives embedded within convertible debt	112,062	172,128
Option Model [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Assets And Liabilities, Quantitative Information [Line Items]
Warrants	1,935	769
Discounted Cash Flow [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Assets And Liabilities, Quantitative Information [Line Items]
Fair value of derivatives embedded within convertible debt	$ 112,062	$ 172,128
Warrant [Member] | Option Model [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Assets And Liabilities, Quantitative Information [Line Items]
Stock price (dollars per share)	$ 3.13	$ 1.40
Exercise price (dollars per share)	$ 1.68	$ 1.68
Term (in years)	2.8	3.8
Volatility	53.82%	76.87%
Dividend rate	0.00%	0.00%
Risk-free return	0.72%	0.50%
Derivative Financial Instruments, Liabilities [Member] | Discounted Cash Flow [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Assets And Liabilities, Quantitative Information [Line Items]
Stock price (dollars per share)	$ 16.37	$ 14.87
Volatility	18.00%
Dividend rate		18.00%
Assumed annual stock dividend	5.00%	5.00%
Assumed annual cash dividend (dollars per share)	$ 1.60	$ 1.60
Convertible trading price	118.70%
Average spread of unsecured debt		109.00%
Implied credit spread		10.50%
Discount rate	8.00%
Minimum [Member] | Derivative Financial Instruments, Liabilities [Member] | Discounted Cash Flow [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Assets And Liabilities, Quantitative Information [Line Items]
Implied credit spread		10.00%
Discount rate	7.50%
Maximum [Member] | Derivative Financial Instruments, Liabilities [Member] | Discounted Cash Flow [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Inputs, Assets And Liabilities, Quantitative Information [Line Items]
Implied credit spread		11.00%
Discount rate	8.50%