Geographic Concentrations of Credit Risk Exceeding 5% of Total Loan Balances (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($)
TEXAS
Concentration Risk [Line Items]
Principal Balance	$ 749,569
TEXAS | Securitized Loans [Member] | Credit Concentration Risk [Member]
Concentration Risk [Line Items]
Percentage Balance	29.40%
FLORIDA
Concentration Risk [Line Items]
Principal Balance	$ 391,215
FLORIDA | Securitized Loans [Member] | Credit Concentration Risk [Member]
Concentration Risk [Line Items]
Percentage Balance	15.30%
OHIO
Concentration Risk [Line Items]
Principal Balance	$ 197,455
OHIO | Securitized Loans [Member] | Credit Concentration Risk [Member]
Concentration Risk [Line Items]
Percentage Balance	7.70%
NORTH CAROLINA
Concentration Risk [Line Items]
Principal Balance	$ 537,375
NORTH CAROLINA | Securitized Loans [Member] | Credit Concentration Risk [Member]
Concentration Risk [Line Items]
Percentage Balance	21.00%