2.4.0.81046 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Detail)truefalsefalse1false falsefalseeol_PE798-----1310-Q0007_STD_181_20130630_0http://www.sec.gov/CIK0000930236duration2013-01-01T00:00:002013-06-30T00:00:00pureStandardhttp://www.xbrl.org/2003/instancepure01true 3rwt_SignificantAccountingPoliciesLineItemsrwt_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Significant Accounting Policies [Line Items]2false 4us-gaap_DebtInstrumentMaturityDateus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse002018-04-15falsefalsetruexbrli:dateItemTypedateDate when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 false0Debt instrument maturity date3false 4rwt_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardHoldingPeriodrwt_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse003 yearsfalsefalsefalsexbrli:durationItemTypenaShare-Based Compensation Arrangement By Share-Based Payment Award, Award Holding PeriodNo definition available.false0Incentive Plan, mandatory holding period before awards vest4false 4rwt_EmployeeStockPurchasePlanMinimumPercentageOfCommonStockFairValueDefinedToPurchaseSharesByEligibleParticipantsrwt_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truetruefalse0.850.85falsefalsefalsenum:percentItemTypepureEmployee Stock Purchase Plan, Minimum Percentage of Common Stock Fair Value Defined to Purchase Shares By Eligible ParticipantsNo definition available.false0Employee Stock Purchase Plan, percentage of common stock fair value that employees can purchase5false 4us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercentus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truetruefalse1.001.00falsefalsefalsenum:percentItemTypepureMaximum percentage of employee gross pay the employee may contribute to a defined contribution plan.No definition available.false0Employees maximum 401(k) contribution6false 4rwt_MinimumPercentageOfTaxableIncomeDistributionToShareholdersrwt_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truetruefalse0.900.90falsefalsefalsenum:percentItemTypepureMinimum Percentage of Taxable Income Distribution to ShareholdersNo definition available.false0Minimum percentage of taxable income distribution to shareholders to be taxed as a REIT7false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2false truefalseeol_PE798-----1310-Q0007_STD_181_20130630_0_711502x711169http://www.sec.gov/CIK0000930236duration2013-01-01T00:00:002013-06-30T00:00:00falsefalseMinimumus-gaap_RangeAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_MinimumMemberus-gaap_RangeAxisexplicitMembernanafalse0Minimum8true 3rwt_SignificantAccountingPoliciesLineItemsrwt_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Significant Accounting Policies [Line Items]9false 4us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1us-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse003 yearsfalsefalsefalsexbrli:durationItemTypenaPeriod which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 false0Incentive Plan, awards vesting period10false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse3false truefalseeol_PE798-----1310-Q0007_STD_181_20130630_0_711502x716112http://www.sec.gov/CIK0000930236duration2013-01-01T00:00:002013-06-30T00:00:00falsefalseMaximumus-gaap_RangeAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_MaximumMemberus-gaap_RangeAxisexplicitMembernanafalse0Maximum11true 3rwt_SignificantAccountingPoliciesLineItemsrwt_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Significant Accounting Policies [Line Items]12false 4us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1us-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse004 yearsfalsefalsefalsexbrli:durationItemTypenaPeriod which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 false0Incentive Plan, awards vesting periodfalseSummary of Significant Accounting Policies - Additional Information (Detail)UnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.redwoodtrust.com/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformation112