Convertible Preferred Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended				1 Months Ended	3 Months Ended	1 Months Ended		3 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Feb. 28, 2009	Jan. 31, 2009 Series A-2 Cumulative Convertible Preferred Stock [Member]	Mar. 31, 2009 Series A-2 Cumulative Convertible Preferred Stock [Member]	May 31, 2010 Series A-1 Cumulative Convertible Preferred Stock [Member]	Feb. 28, 2009 Series A-1 Cumulative Convertible Preferred Stock [Member]	Sep. 30, 2009 Series A-1 Cumulative Convertible Preferred Stock [Member]	Dec. 31, 2011 Minimum [Member]
Temporary Equity [Line Items]
Cumulative convertible preferred stock					$ 30			$ 25
Cumulative convertible preferred stock	1
Cumulative convertible preferred stock							5		19
Common stock issued and delivered	361,402				5,938,776		1,807,011		6,866,641
Beneficial conversion charges						29.3		24.1
Shares to be issued upon a conversion					1,964,058			1,666,668
Additional shares delivered								7,368,388
Additional shares					3,974,718
Net proceeds received from the issuance cumulative convertible preferred stock					29.3
Reset price per share				$ 2.767				$ 2.767
Shares to be received in future conversions								9,035,056
Convertible preferred stock outstanding		$ 1
Preferred stock, dividend rate	4.00%	4.00%	4.00%							4.00%