2.4.0.81065 - Disclosure - Carrying Value for Residential Loans Held-for-Investment (Detail)truefalseIn Thousands, unless otherwise specifiedfalse1false USDfalsefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2false USDfalsefalse$eol_PE798-----1310-Q0007_STD_0_20121231_0http://www.sec.gov/CIK0000930236instant2012-12-31T00:00:000001-01-01T00:00:00iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 3us-gaap_MortgageLoansOnRealEstateLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Mortgage Loans on Real Estate [Line Items]2false 4us-gaap_LoansAndLeasesReceivableNetReportedAmountConsumerus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalsetotalLabel1truefalsefalse32192760003219276USD$falsetruefalse2truefalsefalse28354700002835470USD$falsetruefalsexbrli:monetaryItemTypemonetaryAmount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of consumer loans, including, but not limited to, mortgage, home equity, vehicles, credit card, installment, and lease financing. Excludes loans and leases covered under loss sharing agreements.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5074-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5066-111524 true2Carrying Value3false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_713971x785036http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseResidential Loans Held for Investmentus-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxisxbrldihttp://xbrl.org/2006/xbrldirwt_ResidentialLoansHeldForInvestmentMemberus-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxisexplicitMemberiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Residential Loans Held for Investment4true 3us-gaap_MortgageLoansOnRealEstateLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Mortgage Loans on Real Estate [Line Items]5false 4us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritizedus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse20015440002001544USD$falsefalsefalse2truefalsefalse22780690002278069USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThis is the sum of principal amount outstanding for both securitized and unsecuritized loans of all types.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=13989330&loc=d3e107314-111719 false2Principal balance6false 4us-gaap_UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiumsus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse1978400019784USD$falsefalsefalse2truefalsefalse2324700023247USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6378536&loc=d3e10092-111533 false2Unamortized premium, net7false 4us-gaap_NotesReceivableNetus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalsetotalLabel1truefalsefalse20213280002021328USD$falsefalsefalse2truefalsefalse23013160002301316USD$falsefalsefalsexbrli:monetaryItemTypemonetaryNet amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.3) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 3 -Article 5 true2Recorded investment8false 4us-gaap_AllowanceForLoanAndLeaseLossesRealEstateus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-23150000-23150USD$falsefalsefalse2truefalsefalse-28504000-28504USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe reserve to cover probable credit losses related to specifically identified fixed maturity real estate loans as well as probable credit losses inherent in the remainder of that loan portfolio.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 310 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6873192&loc=d3e21338-158488 false2Allowance for loan losses9false 4us-gaap_LoansAndLeasesReceivableNetReportedAmountConsumerus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalsetotalLabel1truefalsefalse19981780001998178USD$falsetruefalse2truefalsefalse22728120002272812USD$falsetruefalsexbrli:monetaryItemTypemonetaryAmount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of consumer loans, including, but not limited to, mortgage, home equity, vehicles, credit card, installment, and lease financing. Excludes loans and leases covered under loss sharing agreements.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5074-111524 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5066-111524 true2Carrying ValuefalseCarrying Value for Residential Loans Held-for-Investment (Detail) (USD $)ThousandsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.redwoodtrust.com/taxonomy/role/DisclosureCarryingValueForResidentialLoansHeldforInvestment29