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	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Warrants	$ 1,647	$ 1,935
Fair value of derivatives embedded within convertible debt	191,554	112,062
Option Model [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Warrants	1,647	1,935
Discounted Cash Flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value of derivatives embedded within convertible debt	$ 191,554	$ 112,062
Warrants (1) | Option Model [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Stock price (dollars per share)	$ 3.15	$ 3.13
Exercise price (dollars per share)	$ 1.68	$ 1.68
Term (in years)	2 years 4 months 24 days	2 years 9 months 18 days
Volatility	45.83%	53.82%
Dividend rate	0.00%	0.00%
Risk-free return	0.70%	0.72%
Derivative Financial Instruments, Liabilities [Member] | Discounted Cash Flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Stock price (dollars per share)	$ 20.68	$ 16.37
Volatility	16.00%	18.00%
Assumed annual stock dividend	5.00%	5.00%
Assumed annual cash dividend (dollars per share)	$ 1.60	$ 1.60
Convertible trading price	107.19%	118.70%
Implied credit spread	6.00%	8.00%
Minimum [Member] | Derivative Financial Instruments, Liabilities [Member] | Discounted Cash Flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Implied credit spread	5.50%	7.50%
Maximum [Member] | Derivative Financial Instruments, Liabilities [Member] | Discounted Cash Flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Implied credit spread	6.50%	8.50%