Commercial Mortgage Residual Interests Details (Sensitivity Analysis Table) (Details) (USD $) In Thousands, unless otherwise specified											12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Fair Value at 27% Discount Rate [Member]	Dec. 31, 2012 Fair Value at 30% discount rate [Member]	Dec. 31, 2012 Fair Value of 1% Increases Above the CPR Index [Member]	Dec. 31, 2012 Fair Value of 2% Increases Above the CPR Index [Member]	Dec. 31, 2012 Fair Value 2% Adverse Change [Member]	Dec. 31, 2012 Fair Value 3% Adverse Change [Member]	Dec. 31, 2012 Fair Value of Prime Libor Spread Contracting 25 Basis Points [Member]	Dec. 31, 2012 Fair Value of Prime Libor Spread Contracting 50 Basis Points [Member]	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2012 Maximum [Member]
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Carrying amount of retained interests	$ 13,096	$ 15,299
Discount rate assumption			12,546	11,783
Discount rate assumption, percent											27.00%	30.00%
Prepayment speed assumption					13,107	13,106
Prepayment speed assumption, percent											1.00%	2.00%
Expected credit losses							12,844	12,715
Expected credit losses, percent											2.00%	3.00%
Yield Assumptions									$ 13,326	$ 13,555
Yield Assumptions, basis point											0.25%	0.50%