Real Estate Securities - Summary of Significant Valuation Assumptions for Available for Sale Securities (Detail) - Jun. 30, 2015	Total
Prime | Minimum
Schedule of Available-for-sale Securities [Line Items]
Prepayment rates	8.00%
Projected default rate	1.00%
Prime | Maximum
Schedule of Available-for-sale Securities [Line Items]
Prepayment rates	16.00%
Projected default rate	21.00%
Non-prime | Minimum
Schedule of Available-for-sale Securities [Line Items]
Prepayment rates	8.00%
Projected default rate	14.00%
Non-prime | Maximum
Schedule of Available-for-sale Securities [Line Items]
Prepayment rates	12.00%
Projected default rate	18.00%