Financing (Details 6) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Debt Conversion [Line Items]
Gain from changes in fair value of hybrid instruments	$ (545)	$ 24,487
Debentures 2006 Series [Member]
Debt Conversion [Line Items]
Gain from changes in fair value of hybrid instruments	(33)	5,682
Debentures 2007 Series [Member]
Debt Conversion [Line Items]
Gain from changes in fair value of hybrid instruments	(417)	6,789
Debentures 2008 Series [Member]
Debt Conversion [Line Items]
Gain from changes in fair value of hybrid instruments	7	4,776
Debentures 2009 Series [Member]
Debt Conversion [Line Items]
Gain from changes in fair value of hybrid instruments	(4)	1,448
Debentures 2010 Series [Member]
Debt Conversion [Line Items]
Gain from changes in fair value of hybrid instruments	0	2,571
Debentures 2011 Series [Member]
Debt Conversion [Line Items]
Gain from changes in fair value of hybrid instruments	(12)	1,729
Debentures 2012 Series [Member]
Debt Conversion [Line Items]
Gain from changes in fair value of hybrid instruments	379	1,492
Debentures 2013 Series [Member]
Debt Conversion [Line Items]
Gain from changes in fair value of hybrid instruments	$ (465)	$ 0