Mortgage Loans Held for Investment, at Fair Value (Schedule of Concentrations of Credit Risk) (Details) (Mortgage Loans [Member])	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Loans with Unpaid Principal Balance in Excess of Fair Value of Collateral [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	55.70%	73.60%
Geographic Concentration Risk [Member] | California [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	26.20%	25.60%
Geographic Concentration Risk [Member] | Florida [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	16.60%	17.80%
Geographic Concentration Risk [Member] | Georgia [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	5.70%	6.80%
Geographic Concentration Risk [Member] | New York [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	5.10%