11. Fair Value measurements (Details 4) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2011
Qualitative information about level 3 fair value measurements
Fair Values	$ 77,484	$ 160,253
NotesReceivableMember
Qualitative information about level 3 fair value measurements
Fair Values	77,484	160,253
Valuation Techniques	Discounted cash flows	Discounted cash flows
Unobservable Inputs, Discount rate	20.40%	20.40%
Unobservable Inputs, Cumulative net losses	5.50%	5.50%
Unobservable Inputs, Monthly average prepayments	0.50%	0.50%
ResidualInterestSecuritizationsMember
Qualitative information about level 3 fair value measurements
Fair Values	$ 4,895	$ 4,414
Valuation Techniques	Discounted cash flows	Discounted cash flows
Unobservable Inputs, Discount rate	20.00%	20.00%
Unobservable Inputs, Cumulative net losses	13.50%	13.00%
Unobservable Inputs, Monthly average prepayments	0.50%	0.50%