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Loan Product Type and Accompanying Loan Characteristics of Residential Loans (Detail) (USD $) In Thousands, unless otherwise specified | 12 Months Ended
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Dec. 31, 2014 Contract | Dec. 31, 2013 Contract
Residential Loans Held for Investment |  |  |  |
Mortgage Loans on Real Estate [Line Items] |  |  |  |
Number of Loans | 5,315 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember |  | 6,206 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember |
Total Principal | $ 1,483,213 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember |  | $ 1,770,803 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember |
30-89 Days DQ | 41,248 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember |  | 48,449 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember |
90+ Days DQ | 69,562 us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember |  | 78,734 us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember |
Residential Loans Held for Investment | ARM Loans |  |  |  |
Mortgage Loans on Real Estate [Line Items] |  |  |  |
Number of Loans | 5,063 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember |  | 5,903 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember |
Total Principal | 1,311,514 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember |  | 1,557,975 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember |
30-89 Days DQ | 41,248 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember |  | 47,517 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember |
90+ Days DQ | 68,517 us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember |  | 78,384 us-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 | 0 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |  | 0 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |
Loan Balance, maximum | 250 rwt_MortgageLoanOnRealEstateMaximumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |  | 250 rwt_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 | 3,400 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |  | 3,917 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |
Total Principal | 400,779 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |  | 449,458 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |
30-89 Days DQ | 14,604 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |  | 16,038 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |
90+ Days DQ | 16,332 us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |  | 16,856 us-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 | 251 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  | 251 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |
Loan Balance, maximum | 500 rwt_MortgageLoanOnRealEstateMaximumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  | 500 rwt_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 | 1,041 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  | 1,231 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |
Total Principal | 360,848 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  | 428,503 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |
30-89 Days DQ | 14,536 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  | 14,111 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |
90+ Days DQ | 13,955 us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  | 15,775 us-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 | 501 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  | 501 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |
Loan Balance, maximum | 750 rwt_MortgageLoanOnRealEstateMaximumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  | 750 rwt_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 | 328 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  | 395 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |
Total Principal | 198,661 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  | 240,407 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |
30-89 Days DQ | 7,218 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  | 8,951 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |
90+ Days DQ | 12,862 us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  | 14,527 us-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 | 751 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |  | 751 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |
Loan Balance, maximum | 1,000 rwt_MortgageLoanOnRealEstateMaximumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |  | 1,000 rwt_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 | 162 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |  | 191 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |
Total Principal | 143,687 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |  | 170,454 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |
30-89 Days DQ | 2,396 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |  | 3,108 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |
90+ Days DQ | 9,262 us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |  | 7,886 us-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 | 1,000 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFiveMember |  | 1,000 rwt_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 | 132 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFiveMember |  | 169 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFiveMember |
Total Principal | 207,539 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFiveMember |  | 269,153 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFiveMember |
30-89 Days DQ | 2,494 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFiveMember |  | 5,309 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFiveMember |
90+ Days DQ | 16,106 us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember / us-gaap_RangeAxis = rwt_RangeFiveMember |  | 23,340 us-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 | 70 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember |  | 92 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember |
Total Principal | 46,310 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember |  | 62,549 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember |
30-89 Days DQ |  |  | 932 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember |
90+ Days DQ | 319 us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember |  | 350 us-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 | 0 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeOneMember |  | 0 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeOneMember |
Loan Balance, maximum | 250 rwt_MortgageLoanOnRealEstateMaximumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeOneMember |  | 250 rwt_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 | 3 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeOneMember |  | 2 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeOneMember |
Total Principal | 364 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeOneMember |  | 428 us-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 | 251 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  | 251 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeTwoMember |
Loan Balance, maximum | 500 rwt_MortgageLoanOnRealEstateMaximumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  | 500 rwt_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 | 26 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  | 34 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeTwoMember |
Total Principal | 10,056 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  | 13,491 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeTwoMember |
30-89 Days DQ |  |  | 335 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeTwoMember |
90+ Days DQ | 319 us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  | 350 us-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 | 501 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  | 501 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeThreeMember |
Loan Balance, maximum | 750 rwt_MortgageLoanOnRealEstateMaximumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  | 750 rwt_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 | 23 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  | 26 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeThreeMember |
Total Principal | 14,711 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  | 16,376 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeThreeMember |
30-89 Days DQ |  |  | 597 rwt_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 | 751 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeFourMember |  | 751 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeFourMember |
Loan Balance, maximum | 1,000 rwt_MortgageLoanOnRealEstateMaximumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeFourMember |  | 1,000 rwt_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 | 11 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeFourMember |  | 20 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeFourMember |
Total Principal | 9,393 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeFourMember |  | 16,592 us-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 | 1,000 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeFiveMember |  | 1,000 rwt_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 | 7 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeFiveMember |  | 10 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeFiveMember |
Total Principal | 11,786 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeFiveMember |  | 15,662 us-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 | 182 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember |  | 211 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember |
Total Principal | 125,389 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember |  | 150,279 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember |
90+ Days DQ | 726 us-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 | 0 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |  | 0 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |
Loan Balance, maximum | 250 rwt_MortgageLoanOnRealEstateMaximumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |  | 250 rwt_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 | 7 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |  | 9 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |
Total Principal | 1,040 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |  | 1,529 us-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 | 251 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  | 251 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |
Loan Balance, maximum | 500 rwt_MortgageLoanOnRealEstateMaximumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  | 500 rwt_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 | 42 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  | 40 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |
Total Principal | 17,574 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  | 16,929 us-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 | 501 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  | 501 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |
Loan Balance, maximum | 750 rwt_MortgageLoanOnRealEstateMaximumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  | 750 rwt_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 | 71 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  | 86 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |
Total Principal | 42,609 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  | 52,642 us-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 | 751 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |  | 751 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |
Loan Balance, maximum | 1,000 rwt_MortgageLoanOnRealEstateMaximumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |  | 1,000 rwt_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 | 38 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |  | 47 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |
Total Principal | 32,966 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |  | 41,225 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |
90+ Days DQ | 726 us-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 | 1,000 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeFiveMember |  | 1,000 rwt_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 | 24 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeFiveMember |  | 29 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeFiveMember |
Total Principal | 31,200 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeFiveMember |  | 37,954 us-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 | 2,282 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember |  | 547 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember |
Total Principal | 1,305,493 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember |  | 400,873 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember |
30-89 Days DQ | 1,348 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember |  | 166 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember |
90+ Days DQ | 471 us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember |  | 352 us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember |
Residential Loans Held For Sale | ARM Loans |  |  |  |
Mortgage Loans on Real Estate [Line Items] |  |  |  |
Loan Balance, minimum | 66 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember |  |  |
Loan Balance, maximum | 359 rwt_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 | 8 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember |  | 9 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember |
Total Principal | 1,286 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember |  | 1,490 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember |
30-89 Days DQ | 170 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember |  | 166 rwt_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoansForThirtyToNinetyDays / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember |
90+ Days DQ | 471 us-gaap_MortgageLoansOnRealEstatePrincipalAmountOfDelinquentLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_AdjustableRateMortgageLoansMember |  | 352 us-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 | 252 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember |  |  |
Loan Balance, maximum | 1,985 rwt_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 | 109 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember |  | 114 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember |
Total Principal | 84,271 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember |  | 91,976 us-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 | 75 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember |  |  |
Loan Balance, maximum | 2,496 rwt_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 | 2,165 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember |  | 424 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember |
Total Principal | 1,219,936 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember |  | 307,407 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForSaleMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember |
30-89 Days DQ | 1,178 rwt_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 | 804 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember |  |  |
Total Principal | 566,372 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember |  |  |
30-89 Days DQ | 2,137 rwt_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 | 251 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeOneMember |  |  |
Loan Balance, maximum | 500 rwt_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 | 29 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeOneMember |  |  |
Total Principal | 12,487 us-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 | 501 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  |  |
Loan Balance, maximum | 750 rwt_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 | 80 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  |  |
Total Principal | 49,085 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  |  |
30-89 Days DQ | 619 rwt_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 | 751 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  |  |
Loan Balance, maximum | 1,000 rwt_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 | 51 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  |  |
Total Principal | 43,835 us-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 | 1,000 rwt_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 | 14 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeFourMember |  |  |
Total Principal | 17,720 us-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 | 174 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeFiveMember |  |  |
Total Principal | 123,127 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_HybridAdjustableRateMortgageLoanMember / us-gaap_RangeAxis = rwt_RangeFiveMember |  |  |
30-89 Days DQ | 619 rwt_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 | 630 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember |  |  |
Total Principal | 443,245 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember |  |  |
30-89 Days DQ | 1,518 rwt_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 | 0 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |  |  |
Loan Balance, maximum | 250 rwt_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 | 1 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeOneMember |  |  |
Total Principal | 75 us-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 | 251 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  |  |
Loan Balance, maximum | 500 rwt_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 | 158 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  |  |
Total Principal | 72,931 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeTwoMember |  |  |
30-89 Days DQ | 894 rwt_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 | 501 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  |  |
Loan Balance, maximum | 750 rwt_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 | 272 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  |  |
Total Principal | 165,574 us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeThreeMember |  |  |
30-89 Days DQ | 624 rwt_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 | 751 rwt_MortgageLoanOnRealEstateMinimumAmount / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |  |  |
Loan Balance, maximum | 1,000 rwt_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 | 136 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeFourMember |  |  |
Total Principal | 116,892 us-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 | 1,000 rwt_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 | 63 us-gaap_MortgageLoansOnRealEstateNumberOfLoans / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = rwt_ResidentialLoansHeldForInvestmentAtFairValueMember / us-gaap_MortgageLoansOnRealEstateLoanTypeAxis = rwt_FixedLoansMember / us-gaap_RangeAxis = rwt_RangeFiveMember |  |  |
Total Principal | $ 87,773 us-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.

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- Definition Amount of principal due on loans that have been delinquent thirty to eighty-nine days as of the balance sheet date. + References No definition available. + Details
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- Definition The highest stated interest rate within the mortgage loans included in the loan grouping. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule IV) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 310 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-29.3) -URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 29 -Article 12 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph c -Subparagraph Schedule IV -Article 5 + Details
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- Definition The lowest stated interest rate within the mortgage loans included in the loan grouping. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule IV) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 310 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-29.3) -URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 29 -Article 12 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph c -Subparagraph Schedule IV -Article 5 + Details
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- Definition Indicates the number of mortgages under each classification. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule IV) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 310 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-29.3) -URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph c -Subparagraph Schedule IV -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 29 -Paragraph 3 -Article 12 + Details
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- Definition Amount of principal due on loans that have been delinquent, which may exclude loans having interest delinquent for three months or less, as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule IV) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 29 -Article 12 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph c -Subparagraph Schedule IV -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 310 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-29.10(a)) -URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014 + Details
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- Definition This is the sum of principal amount outstanding for both securitized and unsecuritized loans of all types. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=13989330&loc=d3e107314-111719 + Details
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