Assets and Liabilities Measured at Fair Value on Non-Recurring Basis (Detail) (Fair Value, Measurements, Nonrecurring, USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Residential loans, at lower of cost or fair value	$ 1,095
REO	1,692
Residential Loans at Lower of Cost or Fair Value
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Gain (Loss) on assets measured at fair value on a non-recurring basis	5
REO
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Gain (Loss) on assets measured at fair value on a non-recurring basis	(35)
Level 3
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Residential loans, at lower of cost or fair value	1,095
REO	$ 1,692