Fair Value of Financial Instruments Significant Unobservable Inputs Level 3 (Details) (Fair Value, Inputs, Level 3 [Member])	3 Months Ended
	Mar. 31, 2013
Non-Agency CMBS [Member]
Fair Value Inputs, Quantitative Information [Abstract]
Fair Value Inputs, Prepayment Rate	20.00%	[1]
Fair Value Inputs, Probability of Default	2.50%	[1]
Fair Value Inputs, Loss Severity	35.00%	[1]
Fair Value Inputs, Discount Rate	5.10%	[1]
Non-Agency RMBS [Member]
Fair Value Inputs, Quantitative Information [Abstract]
Fair Value Inputs, Prepayment Rate	9.00%	[1]
Fair Value Inputs, Probability of Default	0.90%	[1]
Fair Value Inputs, Loss Severity	18.50%	[1]
Fair Value Inputs, Discount Rate	6.70%	[1]

[1] Data presented are weighted averages.