Fair Value Measurements Narrative (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of senior secured notes	$ 235,725
Carrying value of senior secured notes	205,380
Estimated fair value of convertible debt	89,370
Carrying value of convertible debt	40,722
Forward Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative, Notional Amount	11,156
Gain (Losses) as a result of changes in the fair value of the contracts	$ (286)	$ (1,299)
Convertible Notes due December 15, 2017 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stock price at the end of the period	$ 14.69
Expected volatility	27.20%
Credit spreads	5.05%
Risk-free interest rate	1.32%