Convertible Preferred Stock (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended						12 Months Ended					12 Months Ended
	Dec. 31, 2012 Convertible Preferred Stock item	Dec. 31, 2012 Series A-1 item	Dec. 31, 2012 Series A-1 Liquidation, dissolution, or winding-up, payments to preferred stockholders	Dec. 31, 2012 Series A-1 Minimum	Dec. 31, 2012 Series A-2	Dec. 31, 2011 Series A-2	Dec. 31, 2012 Series A-2 After payment in full of required Series A-1 preferred dividends	Dec. 31, 2012 Series A-2 Liquidation, dissolution, or winding-up, payments to preferred stockholders after distribution to Series A-1 preferred stockholders	Dec. 31, 2012 Series A-2 Minimum	Dec. 31, 2012 Series A-3	Dec. 31, 2011 Series A-3	Dec. 31, 2012 Series A-3 After payment in full of required Series A-1 and A-2 preferred dividends	Dec. 31, 2012 Series A-3 Liquidation, dissolution, or winding-up, payments to preferred stockholders after distribution to Series A-1 and Series A-2 preferred stockholders	Dec. 31, 2012 Series A-3 Minimum	Dec. 31, 2012 Series A-4	Dec. 31, 2011 Series A-4	Dec. 31, 2012 Series A-4 Liquidation, dissolution, or winding-up, payments to preferred stockholders after distribution to Series A-1, Series A-2 , Series A-3, Series A-5 and Series A-6 preferred stockholders	Dec. 31, 2012 Series A-5 Liquidation, dissolution, or winding-up, payments to preferred stockholders after distribution to Series A-1 and Series A-2 preferred stockholders	Dec. 31, 2012 Series A-6 Liquidation, dissolution, or winding-up, payments to preferred stockholders after distribution to Series A-1 and Series A-2 preferred stockholders
Convertible Preferred Stock
Purchase price per share of convertible preferred stock (in dollars per share)	$ 81.42		$ 81.42					$ 81.42					$ 81.42				$ 81.42	$ 81.42	$ 81.42
Conversion price per share (in dollars per share)	$ 8.142
Preferred Stock conversion ratio	10				0.1	0.1				0.1	0.1				0.1	0.1
Percentage of outstanding shares holders vote required for conversion of all shares of preferred stock				70.00%					70.00%					70.00%
Dividend rate (as a percent)		8.00%					8.00%					8.00%
Accrued dividend		$ 8.2			$ 10.7					$ 1.6
Number of classes of stockholder voting rights, in the aggregate, for preferred stockholders, on an as-if converted basis, together with common stockholders	1
Members of the Company's Board of Directors that can be elected by preferred stockholders		2