Schedule of Unobservable Inputs Used in Level 3 Valuation of Mortgage Loans Held for Investment (Details) - Level 3	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Minimum | Mortgage Loans Held for Investment in Securitization Trusts, at Fair Value
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	2.70%	2.20%
Conditional refinance rate	13.90%	0.00%
Default rate	0.00%	0.00%
Loss severity	10.00%	0.00%
Maximum | Mortgage Loans Held for Investment in Securitization Trusts, at Fair Value
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	3.20%	3.60%
Conditional refinance rate	22.30%	21.30%
Default rate	1.80%	2.00%
Loss severity	22.80%	22.90%
Weighted Average | Mortgage Loans Held for Investment in Securitization Trusts, at Fair Value
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	3.00%	3.30%
Conditional refinance rate	17.20%	16.40%
Default rate	0.40%	0.50%
Loss severity	13.40%	14.40%
Mortgage Held for Investment, at Fair Value | Minimum
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	2.80%	3.00%
Conditional refinance rate	14.60%	13.60%
Default rate	0.00%	0.00%
Loss severity	10.00%	10.50%
Mortgage Held for Investment, at Fair Value | Maximum
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	3.10%	3.50%
Conditional refinance rate	21.50%	21.70%
Default rate	1.90%	2.10%
Loss severity	21.40%	22.20%
Mortgage Held for Investment, at Fair Value | Weighted Average
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	3.00%	3.30%
Conditional refinance rate	17.40%	16.40%
Default rate	0.40%	0.70%
Loss severity	13.30%	14.90%