Commercial Mortgage Residual Interests (Narrative And Schedule Of Key Assumptions Used In Determining The Value Of The Residuals) (Details) (USD $)	9 Months Ended		12 Months Ended
	Sep. 30, 2011		Dec. 31, 2010
Mortgage Loans On Real Estate [Line Items]
Percent acquired of the non-controlling interest in majority owned and controlled subsidiary			21.10%
Cost to acquire the non-controlling interest in majority owned and controlled subsidiary			$ 1,603,000
Number of securitizations			7
Discount rate	25.00%		25.00%
Loss severity of loans in foreclosure	20.00%		20.00%
LIBOR	Forward 3-month curve		Forward 3-month curve
Prime	Forward curve		Forward curve
Maximum [Member]
Mortgage Loans On Real Estate [Line Items]
Average life equivalent CPR speeds range	20.77%	[1]	20.37%	[1]
Frequency curve default model	14.70%		15.00%
Minimum [Member]
Mortgage Loans On Real Estate [Line Items]
Average life equivalent CPR speeds range	2.18%	[1]	4.35%	[1]
Frequency curve default model	0.20%		0.10%

[1] Conditional prepayment rate