Fair Value Measurement - Additional Information (Detail) - Loans Held for Investment - Appraisal Value	Dec. 31, 2015	Dec. 31, 2014
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-recoverable rate	9.00%	0.00%
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-recoverable rate	73.00%	74.00%
Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-recoverable rate	20.00%	30.00%