Assets and Liabilities of Consolidated Variable Interest Entity's (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013 Entity	Dec. 31, 2012
Variable Interest Entity [Line Items]
Assets	$ 2,573,802	$ 2,901,214
Liabilities	2,216,586	2,532,916
Number of VIEs	26
Residential Loans Held for Investment
Variable Interest Entity [Line Items]
Assets	1,998,178
Commercial Loans Held For Investment
Variable Interest Entity [Line Items]
Assets	270,449
Real Estate Securities
Variable Interest Entity [Line Items]
Assets	294,771
Restricted Cash
Variable Interest Entity [Line Items]
Assets	288
Accrued Interest Receivable
Variable Interest Entity [Line Items]
Assets	6,151
Other Assets
Variable Interest Entity [Line Items]
Assets	3,965
Accrued Interest Payable
Variable Interest Entity [Line Items]
Liabilities	2,290
Asset-backed Securities
Variable Interest Entity [Line Items]
Liabilities	2,214,296
Sequoia
Variable Interest Entity [Line Items]
Assets	2,005,752
Liabilities	1,922,123
Number of VIEs	24
Sequoia | Residential Loans Held for Investment
Variable Interest Entity [Line Items]
Assets	1,998,178
Sequoia | Restricted Cash
Variable Interest Entity [Line Items]
Assets	148
Sequoia | Accrued Interest Receivable
Variable Interest Entity [Line Items]
Assets	3,461
Sequoia | Other Assets
Variable Interest Entity [Line Items]
Assets	3,965
Sequoia | Accrued Interest Payable
Variable Interest Entity [Line Items]
Liabilities	1,509
Sequoia | Asset-backed Securities
Variable Interest Entity [Line Items]
Liabilities	1,920,614
Resecuritization
Variable Interest Entity [Line Items]
Assets	295,524
Liabilities	134,189
Number of VIEs	1
Resecuritization | Real Estate Securities
Variable Interest Entity [Line Items]
Assets	294,771
Resecuritization | Restricted Cash
Variable Interest Entity [Line Items]
Assets	2
Resecuritization | Accrued Interest Receivable
Variable Interest Entity [Line Items]
Assets	751
Resecuritization | Accrued Interest Payable
Variable Interest Entity [Line Items]
Liabilities	33
Resecuritization | Asset-backed Securities
Variable Interest Entity [Line Items]
Liabilities	134,156
Commercial Securitization
Variable Interest Entity [Line Items]
Assets	272,526
Liabilities	160,274
Number of VIEs	1
Commercial Securitization | Commercial Loans Held For Investment
Variable Interest Entity [Line Items]
Assets	270,449
Commercial Securitization | Restricted Cash
Variable Interest Entity [Line Items]
Assets	138
Commercial Securitization | Accrued Interest Receivable
Variable Interest Entity [Line Items]
Assets	1,939
Commercial Securitization | Accrued Interest Payable
Variable Interest Entity [Line Items]
Liabilities	748
Commercial Securitization | Asset-backed Securities
Variable Interest Entity [Line Items]
Liabilities	$ 159,526