XML 54 R75.htm IDEA: XBRL DOCUMENT v2.4.1.9
Loan Product Type and Accompanying Loan Characteristics of Residential Loans (Detail) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Contract
Dec. 31, 2013
Contract
Residential Loans Held for Investment    
Mortgage Loans on Real Estate [Line Items]    
Number of Loans 5,315us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember		 6,206us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
Total Principal $ 1,483,213us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember		 $ 1,770,803us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
30-89 Days DQ 41,248rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember		 48,449rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
90+ Days DQ 69,562us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember		 78,734us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
Residential Loans Held for Investment | ARM Loans    
Mortgage Loans on Real Estate [Line Items]    
Number of Loans 5,063us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember		 5,903us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
Total Principal 1,311,514us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember		 1,557,975us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
30-89 Days DQ 41,248rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember		 47,517rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
90+ Days DQ 68,517us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember		 78,384us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
Residential Loans Held for Investment | ARM Loans | Range 1    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 0rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 0rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember
Loan Balance, maximum 250rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 250rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember
Interest Rate, minimum 0.25%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1] 0.25%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1]
Interest Rate, maximum 5.50%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1] 6.45%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1]
Maturity start date 2012-12 2012-12
Maturity end date 2035-11 2035-11
Number of Loans 3,400us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 3,917us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember
Total Principal 400,779us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 449,458us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember
30-89 Days DQ 14,604rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 16,038rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember
90+ Days DQ 16,332us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 16,856us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember
Residential Loans Held for Investment | ARM Loans | Range 2    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 251rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 251rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
Loan Balance, maximum 500rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 500rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
Interest Rate, minimum 0.00%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1] (0.13%)us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1]
Interest Rate, maximum 5.63%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1] 5.63%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1]
Maturity start date 2013-12 2013-07
Maturity end date 2036-05 2036-05
Number of Loans 1,041us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 1,231us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
Total Principal 360,848us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 428,503us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
30-89 Days DQ 14,536rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 14,111rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
90+ Days DQ 13,955us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 15,775us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
Residential Loans Held for Investment | ARM Loans | Range 3    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 501rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 501rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember
Loan Balance, maximum 750rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 750rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember
Interest Rate, minimum 0.50%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1] 0.50%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1]
Interest Rate, maximum 4.66%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1] 4.66%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1]
Maturity start date 2013-08 2013-08
Maturity end date 2035-09 2035-09
Number of Loans 328us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 395us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember
Total Principal 198,661us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 240,407us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember
30-89 Days DQ 7,218rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 8,951rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember
90+ Days DQ 12,862us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 14,527us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember
Residential Loans Held for Investment | ARM Loans | Range 4    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 751rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 751rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember
Loan Balance, maximum 1,000rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 1,000rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember
Interest Rate, minimum 0.25%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1] 0.25%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1]
Interest Rate, maximum 2.38%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1] 2.25%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1]
Maturity start date 2019-02 2022-09
Maturity end date 2035-07 2035-07
Number of Loans 162us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 191us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember
Total Principal 143,687us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 170,454us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember
30-89 Days DQ 2,396rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 3,108rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember
90+ Days DQ 9,262us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 7,886us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember
Residential Loans Held for Investment | ARM Loans | Range 5    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 1,000rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 1,000rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember
Interest Rate, minimum 0.00%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 [1] (0.13%)us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 [1]
Interest Rate, maximum 2.63%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 [1] 2.38%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 [1]
Maturity start date 2022-01 2019-02
Maturity end date 2036-05 2036-05
Number of Loans 132us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 169us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember
Total Principal 207,539us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 269,153us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember
30-89 Days DQ 2,494rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 5,309rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember
90+ Days DQ 16,106us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 23,340us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember
Residential Loans Held for Investment | Hybrid ARM Loans    
Mortgage Loans on Real Estate [Line Items]    
Number of Loans 70us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember		 92us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
Total Principal 46,310us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember		 62,549us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
30-89 Days DQ   932rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
90+ Days DQ 319us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember		 350us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
Residential Loans Held for Investment | Hybrid ARM Loans | Range 1    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 0rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 0rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember
Loan Balance, maximum 250rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 250rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember
Interest Rate, minimum 2.63%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1] 2.63%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1]
Interest Rate, maximum 2.63%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1] 4.25%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1]
Maturity start date 2033-09 2033-10
Maturity end date 2034-03 2039-07
Number of Loans 3us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 2us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember
Total Principal 364us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 428us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember
Residential Loans Held for Investment | Hybrid ARM Loans | Range 2    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 251rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 251rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
Loan Balance, maximum 500rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 500rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
Interest Rate, minimum 2.50%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1] 2.63%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1]
Interest Rate, maximum 5.15%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1] 5.15%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1]
Maturity start date 2033-07 2033-07
Maturity end date 2039-12 2040-07
Number of Loans 26us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 34us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
Total Principal 10,056us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 13,491us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
30-89 Days DQ   335rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
90+ Days DQ 319us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 350us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
Residential Loans Held for Investment | Hybrid ARM Loans | Range 3    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 501rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 501rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember
Loan Balance, maximum 750rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 750rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember
Interest Rate, minimum 2.50%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1] 2.63%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1]
Interest Rate, maximum 4.65%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1] 4.75%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1]
Maturity start date 2033-07 2033-07
Maturity end date 2040-09 2040-09
Number of Loans 23us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 26us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember
Total Principal 14,711us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 16,376us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember
30-89 Days DQ   597rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember
Residential Loans Held for Investment | Hybrid ARM Loans | Range 4    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 751rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 751rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember
Loan Balance, maximum 1,000rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 1,000rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember
Interest Rate, minimum 2.50%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1] 2.63%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1]
Interest Rate, maximum 4.80%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1] 4.88%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1]
Maturity start date 2033-07 2033-07
Maturity end date 2040-12 2040-12
Number of Loans 11us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 20us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember
Total Principal 9,393us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 16,592us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember
Residential Loans Held for Investment | Hybrid ARM Loans | Range 5    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 1,000rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 1,000rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember
Interest Rate, minimum 2.50%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 [1] 2.63%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 [1]
Interest Rate, maximum 4.95%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 [1] 4.95%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 [1]
Maturity start date 2033-09 2033-09
Maturity end date 2040-11 2040-11
Number of Loans 7us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 10us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember
Total Principal 11,786us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 15,662us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember
Residential Loans Held for Investment | Fixed Loans    
Mortgage Loans on Real Estate [Line Items]    
Number of Loans 182us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember		 211us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
Total Principal 125,389us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember		 150,279us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
90+ Days DQ 726us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember		  
Residential Loans Held for Investment | Fixed Loans | Range 1    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 0rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 0rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember
Loan Balance, maximum 250rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 250rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember
Interest Rate, minimum 3.70%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1] 3.70%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1]
Interest Rate, maximum 4.90%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1] 4.90%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1]
Maturity start date 2039-04 2039-04
Maturity end date 2041-02 2041-02
Number of Loans 7us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 9us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember
Total Principal 1,040us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 1,529us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember
Residential Loans Held for Investment | Fixed Loans | Range 2    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 251rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 251rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
Loan Balance, maximum 500rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 500rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
Interest Rate, minimum 3.45%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1] 3.45%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1]
Interest Rate, maximum 5.13%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1] 5.63%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1]
Maturity start date 2039-02 2039-02
Maturity end date 2041-07 2041-07
Number of Loans 42us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 40us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
Total Principal 17,574us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 16,929us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember
Residential Loans Held for Investment | Fixed Loans | Range 3    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 501rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 501rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember
Loan Balance, maximum 750rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 750rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember
Interest Rate, minimum 3.65%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1] 3.65%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1]
Interest Rate, maximum 5.25%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1] 5.25%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1]
Maturity start date 2039-02 2039-02
Maturity end date 2041-08 2041-08
Number of Loans 71us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 86us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember
Total Principal 42,609us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 52,642us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember
Residential Loans Held for Investment | Fixed Loans | Range 4    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 751rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 751rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember
Loan Balance, maximum 1,000rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 1,000rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember
Interest Rate, minimum 4.20%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1] 4.20%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1]
Interest Rate, maximum 5.25%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1] 5.25%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1]
Maturity start date 2040-08 2040-08
Maturity end date 2041-08 2041-08
Number of Loans 38us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 47us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember
Total Principal 32,966us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 41,225us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember
90+ Days DQ 726us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		  
Residential Loans Held for Investment | Fixed Loans | Range 5    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 1,000rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 1,000rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember
Interest Rate, minimum 4.30%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 [1] 4.00%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 [1]
Interest Rate, maximum 5.38%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 [1] 5.38%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 [1]
Maturity start date 2040-09 2040-09
Maturity end date 2041-06 2041-06
Number of Loans 24us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 29us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember
Total Principal 31,200us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 37,954us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember
Residential Loans Held For Sale    
Mortgage Loans on Real Estate [Line Items]    
Number of Loans 2,282us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember		 547us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
Total Principal 1,305,493us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember		 400,873us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
30-89 Days DQ 1,348rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember		 166rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
90+ Days DQ 471us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember		 352us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
Residential Loans Held For Sale | ARM Loans    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 66rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember		  
Loan Balance, maximum 359rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember		  
Interest Rate, minimum 1.88%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember		 [1] 1.88%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember		 [1]
Interest Rate, maximum 2.25%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember		 [1] 2.50%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember		 [1]
Maturity start date 2032-11 2032-11
Maturity end date 2033-10 2033-10
Number of Loans 8us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember		 9us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
Total Principal 1,286us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember		 1,490us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
30-89 Days DQ 170rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember		 166rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
90+ Days DQ 471us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember		 352us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_AdjustableRateMortgageLoansMember
Residential Loans Held For Sale | Hybrid ARM Loans    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 252rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember		  
Loan Balance, maximum 1,985rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember		  
Interest Rate, minimum 2.63%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember		 [1] 2.38%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember		 [1]
Interest Rate, maximum 4.00%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember		 [1] 4.63%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember		 [1]
Maturity start date 2037-06 2037-06
Maturity end date 2045-01 2044-01
Number of Loans 109us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember		 114us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
Total Principal 84,271us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember		 91,976us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
Residential Loans Held For Sale | Fixed Loans    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 75rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember		  
Loan Balance, maximum 2,496rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember		  
Interest Rate, minimum 2.88%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember		 [1] 3.13%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember		 [1]
Interest Rate, maximum 5.00%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember		 [1] 5.63%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember		 [1]
Maturity start date 2024-12 2037-06
Maturity end date 2045-01 2044-01
Number of Loans 2,165us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember		 424us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
Total Principal 1,219,936us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember		 307,407us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
30-89 Days DQ 1,178rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForSaleMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember		  
Residential Loans Held For Investment at Fair Value    
Mortgage Loans on Real Estate [Line Items]    
Number of Loans 804us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember		  
Total Principal 566,372us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember		  
30-89 Days DQ 2,137rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember		  
Residential Loans Held For Investment at Fair Value | Hybrid ARM Loans | Range 1    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 251rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		  
Loan Balance, maximum 500rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		  
Interest Rate, minimum 2.38%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1]  
Interest Rate, maximum 3.75%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1]  
Maturity start date 2044-01  
Maturity end date 2044-10  
Number of Loans 29us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		  
Total Principal 12,487us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		  
Residential Loans Held For Investment at Fair Value | Hybrid ARM Loans | Range 2    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 501rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		  
Loan Balance, maximum 750rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		  
Interest Rate, minimum 2.38%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1]  
Interest Rate, maximum 4.25%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1]  
Maturity start date 2044-02  
Maturity end date 2044-11  
Number of Loans 80us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		  
Total Principal 49,085us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		  
30-89 Days DQ 619rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		  
Residential Loans Held For Investment at Fair Value | Hybrid ARM Loans | Range 3    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 751rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		  
Loan Balance, maximum 1,000rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		  
Interest Rate, minimum 2.38%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1]  
Interest Rate, maximum 3.75%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1]  
Maturity start date 2043-05  
Maturity end date 2044-11  
Number of Loans 51us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		  
Total Principal 43,835us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		  
Residential Loans Held For Investment at Fair Value | Hybrid ARM Loans | Range 4    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 1,000rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		  
Interest Rate, minimum 2.38%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1]  
Interest Rate, maximum 3.25%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1]  
Maturity start date 2044-03  
Maturity end date 2044-11  
Number of Loans 14us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		  
Total Principal 17,720us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		  
Residential Loans Held For Investment at Fair Value | Hybrid ARM Loans | Range 5    
Mortgage Loans on Real Estate [Line Items]    
Number of Loans 174us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		  
Total Principal 123,127us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		  
30-89 Days DQ 619rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_HybridAdjustableRateMortgageLoanMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		  
Residential Loans Held For Investment at Fair Value | Fixed Loans    
Mortgage Loans on Real Estate [Line Items]    
Number of Loans 630us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember		  
Total Principal 443,245us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember		  
30-89 Days DQ 1,518rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember		  
Residential Loans Held For Investment at Fair Value | Fixed Loans | Range 1    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 0rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		  
Loan Balance, maximum 250rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		  
Interest Rate, minimum 4.13%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1]  
Interest Rate, maximum 4.13%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		 [1]  
Maturity start date 2044-07  
Maturity end date 2044-07  
Number of Loans 1us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		  
Total Principal 75us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeOneMember		  
Residential Loans Held For Investment at Fair Value | Fixed Loans | Range 2    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 251rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		  
Loan Balance, maximum 500rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		  
Interest Rate, minimum 3.13%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1]  
Interest Rate, maximum 4.75%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		 [1]  
Maturity start date 2029-01  
Maturity end date 2044-12  
Number of Loans 158us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		  
Total Principal 72,931us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		  
30-89 Days DQ 894rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeTwoMember		  
Residential Loans Held For Investment at Fair Value | Fixed Loans | Range 3    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 501rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		  
Loan Balance, maximum 750rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		  
Interest Rate, minimum 3.13%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1]  
Interest Rate, maximum 5.00%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		 [1]  
Maturity start date 2029-04  
Maturity end date 2044-12  
Number of Loans 272us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		  
Total Principal 165,574us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		  
30-89 Days DQ 624rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeThreeMember		  
Residential Loans Held For Investment at Fair Value | Fixed Loans | Range 4    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 751rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		  
Loan Balance, maximum 1,000rwt_MortgageLoanOnRealEstateMaximumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		  
Interest Rate, minimum 3.13%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1]  
Interest Rate, maximum 4.88%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		 [1]  
Maturity start date 2029-01  
Maturity end date 2044-12  
Number of Loans 136us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		  
Total Principal 116,892us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFourMember		  
Residential Loans Held For Investment at Fair Value | Fixed Loans | Range 5    
Mortgage Loans on Real Estate [Line Items]    
Loan Balance, minimum 1,000rwt_MortgageLoanOnRealEstateMinimumAmount
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		  
Interest Rate, minimum 3.25%us-gaap_MortgageLoansOnRealEstateMinimumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 [1]  
Interest Rate, maximum 5.00%us-gaap_MortgageLoansOnRealEstateMaximumInterestRateInRange
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		 [1]  
Maturity start date 2024-01  
Maturity end date 2044-12  
Number of Loans 63us-gaap_MortgageLoansOnRealEstateNumberOfLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		  
Total Principal $ 87,773us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= rwt_ResidentialLoansHeldForInvestmentAtFairValueMember
/ us-gaap_MortgageLoansOnRealEstateLoanTypeAxis
= rwt_FixedLoansMember
/ us-gaap_RangeAxis
= rwt_RangeFiveMember		  
[1] Rate is net of servicing fee for consolidated loans for which we do not own the MSR. For borrowers whose current rate is less than the applicable servicing fee, the rate shown in the table above is zero.