Assets and Liabilities of Consolidated Variable Interest Entity's (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013 Entity	Dec. 31, 2012
Variable Interest Entity [Line Items]
Assets	$ 2,419,786	$ 2,901,214
Liabilities	2,063,758	2,532,916
Number of VIEs	26
Residential Loans Held for Investment
Variable Interest Entity [Line Items]
Assets	1,864,653
Commercial Loans Held For Investment
Variable Interest Entity [Line Items]
Assets	269,255
Real Estate Securities
Variable Interest Entity [Line Items]
Assets	275,763
Restricted Cash
Variable Interest Entity [Line Items]
Assets	297
Accrued Interest Receivable
Variable Interest Entity [Line Items]
Assets	5,676
Other Assets
Variable Interest Entity [Line Items]
Assets	4,142
Accrued Interest Payable
Variable Interest Entity [Line Items]
Liabilities	2,093
Asset-backed Securities
Variable Interest Entity [Line Items]
Liabilities	2,061,665
Sequoia
Variable Interest Entity [Line Items]
Assets	1,871,923
Liabilities	1,792,009
Number of VIEs	24
Sequoia | Residential Loans Held for Investment
Variable Interest Entity [Line Items]
Assets	1,864,653
Sequoia | Restricted Cash
Variable Interest Entity [Line Items]
Assets	159
Sequoia | Accrued Interest Receivable
Variable Interest Entity [Line Items]
Assets	3,061
Sequoia | Other Assets
Variable Interest Entity [Line Items]
Assets	4,050
Sequoia | Accrued Interest Payable
Variable Interest Entity [Line Items]
Liabilities	1,322
Sequoia | Asset-backed Securities
Variable Interest Entity [Line Items]
Liabilities	1,790,687
Resecuritization
Variable Interest Entity [Line Items]
Assets	276,445
Liabilities	112,206
Number of VIEs	1
Resecuritization | Real Estate Securities
Variable Interest Entity [Line Items]
Assets	275,763
Resecuritization | Accrued Interest Receivable
Variable Interest Entity [Line Items]
Assets	682
Resecuritization | Accrued Interest Payable
Variable Interest Entity [Line Items]
Liabilities	27
Resecuritization | Asset-backed Securities
Variable Interest Entity [Line Items]
Liabilities	112,179
Commercial Securitization
Variable Interest Entity [Line Items]
Assets	271,418
Liabilities	159,543
Number of VIEs	1
Commercial Securitization | Commercial Loans Held For Investment
Variable Interest Entity [Line Items]
Assets	269,255
Commercial Securitization | Restricted Cash
Variable Interest Entity [Line Items]
Assets	138
Commercial Securitization | Accrued Interest Receivable
Variable Interest Entity [Line Items]
Assets	1,933
Commercial Securitization | Other Assets
Variable Interest Entity [Line Items]
Assets	92
Commercial Securitization | Accrued Interest Payable
Variable Interest Entity [Line Items]
Liabilities	744
Commercial Securitization | Asset-backed Securities
Variable Interest Entity [Line Items]
Liabilities	$ 158,799