XML 48 R61.htm IDEA: XBRL DOCUMENT
v3.2.0.727

Fair Value of Financial Instruments - Additional Information (Detail) - Jun. 30, 2015 - USD ($) $ in Millions | Total | Total
--- | --- | ---
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |  |
Dealer marks of securities | 81.00% | 81.00%
Percentage of carrying value for which dealer quotes have been received | 92.00% | 92.00%
Residential Subordinate Securities |  |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |  |
Fair value option elected aggregate carrying amount, asset | $ 36 | $ 59
Residential Senior Securities |  |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |  |
Fair value option elected aggregate carrying amount, asset | 33 | 33
Residential Loans |  |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |  |
Fair value option elected aggregate carrying amount, asset | 2,780 | 5,180
Commercial Loans |  |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |  |
Fair value option elected aggregate carrying amount, asset | 258 | 350
Mortgage servicing rights |  |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |  |
Fair value option elected aggregate carrying amount, asset | $ 32 | $ 51
Mortgage servicing rights | Maximum |  |
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] |  |
Percentage difference of internal valuation than dealer marks | 1.00% | 1.00%

X
- Definition Fair Value, Option, Assets, Aggregate Carrying Amount During Period + References No definition available. + Details
Name: | rwt_FairValueOptionAssetsAggregateCarryingAmountDuringPeriod
Namespace Prefix: | rwt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Percentage Difference Of Internal Valuation Than Dealer Marks + References No definition available. + Details
Name: | rwt_PercentageDifferenceOfInternalValuationThanDealerMarks
Namespace Prefix: | rwt_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of Carrying Value for Which Dealer Quotes Were Received on Securities + References No definition available. + Details
Name: | rwt_PercentageOfCarryingValueForWhichDealerQuotesWereReceivedOnSecurities
Namespace Prefix: | rwt_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of Third-party Dealer Quotes Received on Securities. + References No definition available. + Details
Name: | rwt_PercentageOfDealerQuotesReceivedOnSecurities
Namespace Prefix: | rwt_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | invest_InvestmentSecuritiesClassAxis=rwt_ResidentialSubordinateSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_InvestmentSecuritiesClassAxis=rwt_ResidentialSeniorSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_InvestmentSecuritiesClassAxis=rwt_ResidentialLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_InvestmentSecuritiesClassAxis=us-gaap_CommercialLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |