Summary of Carrying Value Components of Collateral for Asset-Backed Securities Issued and Outstanding (Detail) (Asset-backed Securities, USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	$ 2,211,139	$ 2,292,378
Residential Loans
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	1,689,994	1,762,167
Commercial Loans
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	257,375	257,741
Real Estate Securities
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	255,834	263,204
Restricted Cash
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	323	289
Accrued Interest Receivable
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	5,006	5,316
REO
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	2,607	3,661
Sequoia
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	1,695,297	1,768,694
Sequoia | Residential Loans
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	1,689,994	1,762,167
Sequoia | Restricted Cash
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	189	152
Sequoia | Accrued Interest Receivable
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	2,507	2,714
Sequoia | REO
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	2,607	3,661
Residential Resecuritization
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	256,414	263,831
Residential Resecuritization | Real Estate Securities
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	255,834	263,204
Residential Resecuritization | Accrued Interest Receivable
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	580	627
Commercial Securitization
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	259,428	259,853
Commercial Securitization | Commercial Loans
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	257,375	257,741
Commercial Securitization | Restricted Cash
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	134	137
Commercial Securitization | Accrued Interest Receivable
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral for ABS Issued	$ 1,919	$ 1,975