Financing (Details 6) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Debt Conversion [Line Items]
Unrealized Gain Loss On Hybrid Instrument Gross	$ (1,515)	$ (545)
Less: Day-one loss from debenture financings	0	0
Gain (loss) from changes in fair value of hybrid instruments	(1,515)	(545)
Debentures 2006 Series [Member]
Debt Conversion [Line Items]
Unrealized Gain Loss On Hybrid Instrument Gross	(83)	(33)
Debentures 2007 Series [Member]
Debt Conversion [Line Items]
Unrealized Gain Loss On Hybrid Instrument Gross	(34)	(417)
Debentures 2008 Series [Member]
Debt Conversion [Line Items]
Unrealized Gain Loss On Hybrid Instrument Gross	(81)	7
Debentures 2009 Series [Member]
Debt Conversion [Line Items]
Unrealized Gain Loss On Hybrid Instrument Gross	0	(4)
Debentures 2010 Series [Member]
Debt Conversion [Line Items]
Unrealized Gain Loss On Hybrid Instrument Gross	0	0
Debentures 2011 Series [Member]
Debt Conversion [Line Items]
Unrealized Gain Loss On Hybrid Instrument Gross	(34)	(12)
Debentures 2012 Series [Member]
Debt Conversion [Line Items]
Unrealized Gain Loss On Hybrid Instrument Gross	(41)	379
Debentures 2013 Series [Member]
Debt Conversion [Line Items]
Unrealized Gain Loss On Hybrid Instrument Gross	(1,236)	(465)
Debentures 2014 Series [Member]
Debt Conversion [Line Items]
Unrealized Gain Loss On Hybrid Instrument Gross	$ (6)	$ 0