Summary of the Classifications and Carrying Value of Residential and Commercial Real Estate Loans (Detail) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Mortgage Loans on Real Estate [Line Items]
Residential real estate loans	$ 3,860,233	$ 3,797,095
Commercial real estate loans	83,866	50,386
Real Estate Loans	3,944,099	3,847,481
Redwood
Mortgage Loans on Real Estate [Line Items]
Residential real estate loans	205,301	254,936
Commercial real estate loans	71,168	30,536
Real Estate Loans	276,469	285,472
Redwood | Residential Real Estate Loans Held For Sale
Mortgage Loans on Real Estate [Line Items]
Residential real estate loans	1,836	1,855
Redwood | Residential Real Estate Loans Held for Investment
Mortgage Loans on Real Estate [Line Items]
Residential real estate loans	203,465	253,081
Redwood | Commercial Real Estate Loans Held For Investment
Mortgage Loans on Real Estate [Line Items]
Commercial real estate loans	71,168	30,536
Sequoia
Mortgage Loans on Real Estate [Line Items]
Residential real estate loans	3,654,932	3,542,159
Real Estate Loans	3,654,932	3,542,159
Sequoia | Residential Real Estate Loans Held for Investment
Mortgage Loans on Real Estate [Line Items]
Residential real estate loans	3,654,932	3,542,159
Acacia
Mortgage Loans on Real Estate [Line Items]
Commercial real estate loans	12,698	19,850
Real Estate Loans	12,698	19,850
Acacia | Commercial Real Estate Loans at Fair Value
Mortgage Loans on Real Estate [Line Items]
Commercial real estate loans	12,698	19,850
Residential Real Estate Loans Held For Sale
Mortgage Loans on Real Estate [Line Items]
Residential real estate loans	1,836	1,855
Residential Real Estate Loans Held for Investment
Mortgage Loans on Real Estate [Line Items]
Residential real estate loans	3,858,397	3,795,240
Commercial Real Estate Loans at Fair Value
Mortgage Loans on Real Estate [Line Items]
Commercial real estate loans	12,698	19,850
Commercial Real Estate Loans Held For Investment
Mortgage Loans on Real Estate [Line Items]
Commercial real estate loans	$ 71,168	$ 30,536