XML 101 R98.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Components of Carrying Value (Which Equals Fair Value) of Residential Available for Sale Securities (Detail) (USD $) In Thousands, unless otherwise specified | Dec. 31, 2014 | Dec. 31, 2013
--- | --- | ---
Schedule of Available-for-sale Securities [Line Items] |  |
Carrying Value | $ 1,267,624 us-gaap_AvailableForSaleSecurities | $ 1,558,306 us-gaap_AvailableForSaleSecurities
Senior Securities |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Carrying Value | 487,557 us-gaap_AvailableForSaleSecurities / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember | 855,692 us-gaap_AvailableForSaleSecurities / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember
Senior Securities | Prime |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Carrying Value | 307,813 us-gaap_AvailableForSaleSecurities / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember | 662,306 us-gaap_AvailableForSaleSecurities / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember
Senior Securities | Non-prime |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Carrying Value | 179,744 us-gaap_AvailableForSaleSecurities / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember | 193,386 us-gaap_AvailableForSaleSecurities / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember
Re-REMIC |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Carrying Value | 168,347 us-gaap_AvailableForSaleSecurities / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember | 176,376 us-gaap_AvailableForSaleSecurities / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember
Subordinate Securities |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Carrying Value | 611,720 us-gaap_AvailableForSaleSecurities / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember | 526,238 us-gaap_AvailableForSaleSecurities / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember
Residential |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Principal balance | 1,445,079 rwt_AvailableForSaleSecuritiesPrincipalBalance / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 1,808,992 rwt_AvailableForSaleSecuritiesPrincipalBalance / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Credit reserve | (70,067)rwt_AvailableForSaleSecuritiesCreditReserve / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | (116,870)rwt_AvailableForSaleSecuritiesCreditReserve / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Unamortized discount, net | (296,342)rwt_AvailableForSaleSecuritiesUnamortizedDiscountsPremiums / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | (298,469)rwt_AvailableForSaleSecuritiesUnamortizedDiscountsPremiums / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Amortized cost | 1,078,670 us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 1,393,653 us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Amortized cost | 1,078,670 us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 1,393,653 us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Gross unrealized gains | 191,750 us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 187,786 us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Gross unrealized losses | (2,796)us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | (23,133)us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Carrying Value | 1,267,624 us-gaap_AvailableForSaleSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 1,558,306 us-gaap_AvailableForSaleSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Residential | Senior Securities | Prime |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Principal balance | 311,573 rwt_AvailableForSaleSecuritiesPrincipalBalance / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 670,051 rwt_AvailableForSaleSecuritiesPrincipalBalance / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Credit reserve | (3,660)rwt_AvailableForSaleSecuritiesCreditReserve / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | (10,144)rwt_AvailableForSaleSecuritiesCreditReserve / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Unamortized discount, net | (34,782)rwt_AvailableForSaleSecuritiesUnamortizedDiscountsPremiums / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | (44,133)rwt_AvailableForSaleSecuritiesUnamortizedDiscountsPremiums / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Amortized cost | 273,131 us-gaap_AvailableForSaleSecuritiesAmortizedCost / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 615,774 us-gaap_AvailableForSaleSecuritiesAmortizedCost / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Amortized cost | 273,131 us-gaap_AvailableForSaleSecuritiesAmortizedCost / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 615,774 us-gaap_AvailableForSaleSecuritiesAmortizedCost / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Gross unrealized gains | 35,980 us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 47,980 us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Gross unrealized losses | (1,298)us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | (1,448)us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Carrying Value | 307,813 us-gaap_AvailableForSaleSecurities / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 662,306 us-gaap_AvailableForSaleSecurities / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialPrimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Residential | Senior Securities | Non-prime |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Principal balance | 196,258 rwt_AvailableForSaleSecuritiesPrincipalBalance / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 218,603 rwt_AvailableForSaleSecuritiesPrincipalBalance / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Credit reserve | (9,644)rwt_AvailableForSaleSecuritiesCreditReserve / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | (13,840)rwt_AvailableForSaleSecuritiesCreditReserve / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Unamortized discount, net | (31,491)rwt_AvailableForSaleSecuritiesUnamortizedDiscountsPremiums / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | (36,882)rwt_AvailableForSaleSecuritiesUnamortizedDiscountsPremiums / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Amortized cost | 155,123 us-gaap_AvailableForSaleSecuritiesAmortizedCost / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 167,881 us-gaap_AvailableForSaleSecuritiesAmortizedCost / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Amortized cost | 155,123 us-gaap_AvailableForSaleSecuritiesAmortizedCost / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 167,881 us-gaap_AvailableForSaleSecuritiesAmortizedCost / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Gross unrealized gains | 24,682 us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 25,654 us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Gross unrealized losses | (61)us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | (149)us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Carrying Value | 179,744 us-gaap_AvailableForSaleSecurities / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 193,386 us-gaap_AvailableForSaleSecurities / invest_InvestmentSecuritiesClassAxis = us-gaap_ResidentialSubprimeFinancingReceivableMember / us-gaap_InvestmentTypeAxis = rwt_SeniorSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Residential | Re-REMIC |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Principal balance | 195,098 rwt_AvailableForSaleSecuritiesPrincipalBalance / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 214,046 rwt_AvailableForSaleSecuritiesPrincipalBalance / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Credit reserve | (15,202)rwt_AvailableForSaleSecuritiesCreditReserve / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | (30,429)rwt_AvailableForSaleSecuritiesCreditReserve / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Unamortized discount, net | (79,611)rwt_AvailableForSaleSecuritiesUnamortizedDiscountsPremiums / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | (80,188)rwt_AvailableForSaleSecuritiesUnamortizedDiscountsPremiums / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Amortized cost | 100,285 us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 103,429 us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Amortized cost | 100,285 us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 103,429 us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Gross unrealized gains | 68,062 us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 72,947 us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Carrying Value | 168,347 us-gaap_AvailableForSaleSecurities / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 176,376 us-gaap_AvailableForSaleSecurities / us-gaap_InvestmentTypeAxis = rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Residential | Subordinate Securities |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Principal balance | 742,150 rwt_AvailableForSaleSecuritiesPrincipalBalance / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 706,292 rwt_AvailableForSaleSecuritiesPrincipalBalance / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Credit reserve | (41,561)rwt_AvailableForSaleSecuritiesCreditReserve / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | (62,457)rwt_AvailableForSaleSecuritiesCreditReserve / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Unamortized discount, net | (150,458)rwt_AvailableForSaleSecuritiesUnamortizedDiscountsPremiums / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | (137,266)rwt_AvailableForSaleSecuritiesUnamortizedDiscountsPremiums / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Amortized cost | 550,131 us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 506,569 us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Amortized cost | 550,131 us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 506,569 us-gaap_AvailableForSaleSecuritiesAmortizedCost / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Gross unrealized gains | 63,026 us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | 41,205 us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Gross unrealized losses | (1,437)us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | (21,536)us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember
Carrying Value | $ 611,720 us-gaap_AvailableForSaleSecurities / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember | $ 526,238 us-gaap_AvailableForSaleSecurities / us-gaap_InvestmentTypeAxis = rwt_SubordinateSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ResidentialMortgageBackedSecuritiesMember

X
- Definition Balance of credit reserve on available-for-sale securities. + References No definition available. + Details
Name: | rwt_AvailableForSaleSecuritiesCreditReserve
Namespace Prefix: | rwt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Available For Sale Securities Principal Balance + References No definition available. + Details
Name: | rwt_AvailableForSaleSecuritiesPrincipalBalance
Namespace Prefix: | rwt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Balance of net unamortized discount on available-for-sale securities. + References No definition available. + Details
Name: | rwt_AvailableForSaleSecuritiesUnamortizedDiscountsPremiums
Namespace Prefix: | rwt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562 + Details
Name: | us-gaap_AvailableForSaleSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_AvailableForSaleSecuritiesAmortizedCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_InvestmentTypeAxis=rwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=rwt_SeniorSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=rwt_SubordinateSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_ResidentialMortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |