2.4.0.81079 - Disclosure - Real Estate Securities - Additional Information (Detail)truefalsefalse1false USDfalsefalse$eol_PE798-----1310-Q0007_STD_91_20130630_0http://www.sec.gov/CIK0000930236duration2013-04-01T00:00:002013-06-30T00:00:00iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170InvestmentStandardhttp://www.redwoodtrust.com/20130630Investmentrwt0USDUSD$2false USDfalsefalse$eol_PE798-----1310-Q0007_STD_90_20130331_0http://www.sec.gov/CIK0000930236duration2013-01-01T00:00:002013-03-31T00:00:00iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170InvestmentStandardhttp://www.redwoodtrust.com/20130630Investmentrwt0USDUSD$3false USDfalsefalse$eol_PE798-----1310-Q0007_STD_91_20120630_0http://www.sec.gov/CIK0000930236duration2012-04-01T00:00:002012-06-30T00:00:00iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$4false USDfalsefalse$eol_PE798-----1310-Q0007_STD_181_20130630_0http://www.sec.gov/CIK0000930236duration2013-01-01T00:00:002013-06-30T00:00:00iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170InvestmentStandardhttp://www.redwoodtrust.com/20130630Investmentrwt0USDUSD$5false USDfalsefalse$eol_PE798-----1310-Q0007_STD_182_20120630_0http://www.sec.gov/CIK0000930236duration2012-01-01T00:00:002012-06-30T00:00:00iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$6false USDfalsefalse$eol_PE798-----1310-Q0007_STD_0_20121231_0http://www.sec.gov/CIK0000930236instant2012-12-31T00:00:000001-01-01T00:00:00InvestmentStandardhttp://www.redwoodtrust.com/20130630Investmentrwt0iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]2false 4us-gaap_TradingSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse141615000141615000USD$falsetruefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse141615000141615000USD$falsetruefalse5falsefalsefalse00falsefalsefalse6truefalsefalse3317200033172000USD$falsetruefalsexbrli:monetaryItemTypemonetaryAmount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.Reference 1: 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 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.4) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 false2Trading securities3false 4us-gaap_AvailableForSaleSecuritiesGrossRealizedGainsus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse193000193000USD$falsefalsefalse2truefalsefalse1200000012000000USD$falsefalsefalse3truefalsefalse69890006989000USD$falsefalsefalse4truefalsefalse1223100012231000USD$falsefalsefalse5truefalsefalse1477400014774000USD$falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThis item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563 false2Realized gain on sale of available for sale securities4false 4us-gaap_AvailableForSaleSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse11726900001172690000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse11726900001172690000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse10755810001075581000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.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 false2Available-for-sale securities5false 4rwt_NumberOfAvailableForSaleSecuritiesrwt_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse294294falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse294294falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse284284falsefalsefalsexbrli:decimalItemTypedecimalNumber Of Available for Sale SecuritiesNo definition available.false256Number of AFS securities6false 4us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1us-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse4747falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse4747falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse2222falsefalsefalsexbrli:integerItemTypeintegerNumber of investment positions in available-for-sale investments in a continuous unrealized loss position for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563 false256Number of securities in unrealized loss position7false 4rwt_NumberOfSecuritiesContinuousUnrealizedLossPositionMoreThanTwelveMonthsrwt_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse99falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse99falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse1414falsefalsefalsexbrli:integerItemTypeintegerNumber of Securities, Continuous Unrealized Loss Position More Than Twelve MonthsNo definition available.false256Number of securities in a continuous unrealized loss position for twelve consecutive months or longer8false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_710256x795705http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseSenior Securitiesus-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldirwt_SeniorSecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Senior Securities9true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]10false 4us-gaap_TradingSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse141116000141116000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse141116000141116000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse3254300032543000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.4) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 false2Trading securities11false 4us-gaap_AvailableForSaleSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse634846000634846000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse634846000634846000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse711789000711789000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.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 false2Available-for-sale securities12false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse9false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_710256x755223http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseTrading Securitiesus-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldirwt_TradingSecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Trading Securities13true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]14false 4us-gaap_InvestmentOwnedBalancePrincipalAmountus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse1200000012000000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse1200000012000000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse1200000012000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryFor investments which are quantified by principal amount, the principle balance held at close of period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 320 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-12C.Column B) -URI http://asc.fasb.org/extlink&oid=6955306&loc=d3e611225-123010 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 320 -Section S99 -Paragraph 6 -Subparagraph (SX 210.12-14.Column B) -URI http://asc.fasb.org/extlink&oid=6955306&loc=d3e611322-123010 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 320 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-12.Column B) -URI http://asc.fasb.org/extlink&oid=6955306&loc=d3e611133-123010 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 12C -Paragraph Column B -Article 12 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 12 -Paragraph Column B -Article 12 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 14 -Paragraph Column B -Article 12 false2Unpaid principal balance15false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse11false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_710256x777106http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseInterest Only Securitiesus-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldirwt_InterestOnlySecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Interest Only Securities16true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]17false 4us-gaap_TradingSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse141000000141000000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse141000000141000000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.4) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 false2Trading securities18false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse12false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_710256x832718http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseResidential Subordinate Securitiesus-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldirwt_ResidentialSubordinateSecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Residential Subordinate Securities19true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]20false 4us-gaap_TradingSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse242000242000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse242000242000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.4) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 false2Trading securities21false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse13false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_710256x817522http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseRe-REMICus-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldirwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Re-REMIC22true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]23false 4us-gaap_AvailableForSaleSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse154167000154167000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse154167000154167000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse163035000163035000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.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 false2Available-for-sale securities24false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse15false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_710256x838995http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseSubordinate Securitiesus-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldirwt_SubordinateSecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Subordinate Securities25true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]26false 4us-gaap_TradingSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse499000499000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse499000499000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse629000629000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.4) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 false2Trading securities27false 4us-gaap_AvailableForSaleSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse383677000383677000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse383677000383677000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse200757000200757000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.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 false2Available-for-sale securities28false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse17false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_707066x715052_710256x795705http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseResidential Primeinvest_InvestmentSecuritiesClassAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ResidentialPrimeFinancingReceivableMemberinvest_InvestmentSecuritiesClassAxisexplicitMemberfalsefalseSenior Securitiesus-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldirwt_SeniorSecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Residential Prime | Senior Securities29true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]30false 4us-gaap_TradingSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse123591000123591000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse123591000123591000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse1040900010409000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.4) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 false2Trading securities31false 4rwt_SecuritiesFinancedThroughNonrecourseResecuritizationrwt_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse154000000154000000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse154000000154000000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse172000000172000000USD$falsefalsefalsexbrli:monetaryItemTypemonetarySecurities Financed Through Nonrecourse ResecuritizationNo definition available.false2Securities financed through non-recourse resecuritization entity32false 4rwt_LoansUnderlyingrwt_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse80000000008000000000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse80000000008000000000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThe carrying value of loans underlying the security class as of the balance sheet date.No definition available.false2Loans underlying33false 4us-gaap_AvailableForSaleSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse410159000410159000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse410159000410159000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse466523000466523000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562 false2Available-for-sale securities34false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse19false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_707066x715052_710256x817522http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseResidential Primeinvest_InvestmentSecuritiesClassAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ResidentialPrimeFinancingReceivableMemberinvest_InvestmentSecuritiesClassAxisexplicitMemberfalsefalseRe-REMICus-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldirwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Residential Prime | Re-REMIC35true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]36false 4rwt_LoansUnderlyingrwt_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse50000000005000000000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse50000000005000000000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThe carrying value of loans underlying the security class as of the balance sheet date.No definition available.false2Loans underlying37false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse20false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_707066x715052_710256x838995http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseResidential Primeinvest_InvestmentSecuritiesClassAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ResidentialPrimeFinancingReceivableMemberinvest_InvestmentSecuritiesClassAxisexplicitMemberfalsefalseSubordinate Securitiesus-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldirwt_SubordinateSecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Residential Prime | Subordinate Securities38true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]39false 4us-gaap_TradingSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse354000354000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse354000354000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse468000468000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.Reference 1: 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 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.4) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 false2Trading securities40false 4rwt_LoansUnderlyingrwt_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse1600000000016000000000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse1600000000016000000000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThe carrying value of loans underlying the security class as of the balance sheet date.No definition available.false2Loans underlying41false 4us-gaap_AvailableForSaleSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse381631000381631000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse381631000381631000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse184528000184528000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562 false2Available-for-sale securities42false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse22false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_707066x713347_710256x795705http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseResidential non-primeinvest_InvestmentSecuritiesClassAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ResidentialSubprimeFinancingReceivableMemberinvest_InvestmentSecuritiesClassAxisexplicitMemberfalsefalseSenior Securitiesus-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldirwt_SeniorSecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Residential non-prime | Senior Securities43true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]44false 4us-gaap_TradingSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse1752500017525000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse1752500017525000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse2213400022134000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.Reference 1: 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 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.4) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 false2Trading securities45false 4rwt_SecuritiesFinancedThroughNonrecourseResecuritizationrwt_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse141000000141000000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse141000000141000000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse152000000152000000USD$falsefalsefalsexbrli:monetaryItemTypemonetarySecurities Financed Through Nonrecourse ResecuritizationNo definition available.false2Securities financed through non-recourse resecuritization entity46false 4rwt_LoansUnderlyingrwt_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse40000000004000000000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse40000000004000000000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThe carrying value of loans underlying the security class as of the balance sheet date.No definition available.false2Loans underlying47false 4us-gaap_AvailableForSaleSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse224687000224687000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse224687000224687000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse245266000245266000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.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 false2Available-for-sale securities48false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse24false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_707066x713347_710256x817522http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseResidential non-primeinvest_InvestmentSecuritiesClassAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ResidentialSubprimeFinancingReceivableMemberinvest_InvestmentSecuritiesClassAxisexplicitMemberfalsefalseRe-REMICus-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldirwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Residential non-prime | Re-REMIC49true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]50false 4rwt_LoansUnderlyingrwt_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse106000000106000000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse106000000106000000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThe carrying value of loans underlying the security class as of the balance sheet date.No definition available.false2Loans underlying51false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse25false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_707066x713347_710256x838995http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseResidential non-primeinvest_InvestmentSecuritiesClassAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ResidentialSubprimeFinancingReceivableMemberinvest_InvestmentSecuritiesClassAxisexplicitMemberfalsefalseSubordinate Securitiesus-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldirwt_SubordinateSecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Residential non-prime | Subordinate Securities52true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]53false 4us-gaap_TradingSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse145000145000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse145000145000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse161000161000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.4) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 false2Trading securities54false 4rwt_LoansUnderlyingrwt_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse431000000431000000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse431000000431000000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThe carrying value of loans underlying the security class as of the balance sheet date.No definition available.false2Loans underlying55false 4us-gaap_AvailableForSaleSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse20460002046000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse20460002046000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse21600002160000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.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 false2Available-for-sale securities56false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse27false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_707066x707284http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseResidentialinvest_InvestmentSecuritiesClassAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ResidentialMortgageBackedSecuritiesMemberinvest_InvestmentSecuritiesClassAxisexplicitMemberiso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Residential57true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]58false 4us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCostus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse30000003000000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse30000003000000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of available-for-sale debt securities at cost, net of adjustments, maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.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 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27198-111563 false2Marketable securities, due from five to ten years59false 4us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCostus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse30003000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse30003000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of available-for-sale debt securities at cost, net of adjustments, maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.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 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27198-111563 false2Marketable securities, less than five years60false 4rwt_AvailableForSaleSecuritiesCreditReserverwt_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse190410000190410000USD$falsefalsefalse2truefalsefalse190690000190690000USD$falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse190410000190410000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse187032000187032000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryBalance of credit reserve on available-for-sale securities.No definition available.false2Credit reserve61false 4us-gaap_AvailableForSaleSecuritiesus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse11726900001172690000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse11726900001172690000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6truefalsefalse10615120001061512000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562 false2Available-for-sale securities62false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse30false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_707066x707284_710256x795705http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseResidentialinvest_InvestmentSecuritiesClassAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ResidentialMortgageBackedSecuritiesMemberinvest_InvestmentSecuritiesClassAxisexplicitMemberfalsefalseSenior Securitiesus-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldirwt_SeniorSecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberpureStandardhttp://www.xbrl.org/2003/instancepure0iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Residential | Senior Securities63true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]64false 4rwt_AvailableForSaleSecuritiesCreditReserverwt_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse5000000050000000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse5000000050000000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryBalance of credit reserve on available-for-sale securities.No definition available.false2Credit reserve65false 4rwt_DelinquencyRatesrwt_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truetruefalse0.10080.1008falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truetruefalse0.10080.1008falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsenum:percentItemTypepureDelinquency RatesNo definition available.false0Percentage of outstanding loan serious delinquencies66false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse31false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_707066x707284_710256x817522http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseResidentialinvest_InvestmentSecuritiesClassAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ResidentialMortgageBackedSecuritiesMemberinvest_InvestmentSecuritiesClassAxisexplicitMemberfalsefalseRe-REMICus-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldirwt_ResecuritizationOfRealEstateMortgageInvestmentSecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberpureStandardhttp://www.xbrl.org/2003/instancepure0iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Residential | Re-REMIC67true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]68false 4rwt_AvailableForSaleSecuritiesCreditReserverwt_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse4400000044000000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse4400000044000000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryBalance of credit reserve on available-for-sale securities.No definition available.false2Credit reserve69false 4rwt_LoansUnderlyingrwt_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse50000000005000000000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse50000000005000000000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThe carrying value of loans underlying the security class as of the balance sheet date.No definition available.false2Loans underlying70false 4rwt_DelinquencyRatesrwt_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truetruefalse0.09700.0970falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truetruefalse0.09700.0970falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsenum:percentItemTypepureDelinquency RatesNo definition available.false0Percentage of outstanding loan serious delinquencies71false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse32false USDtruefalse$eol_PE798-----1310-Q0007_STD_0_20130630_0_707066x707284_710256x838995http://www.sec.gov/CIK0000930236instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseResidentialinvest_InvestmentSecuritiesClassAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ResidentialMortgageBackedSecuritiesMemberinvest_InvestmentSecuritiesClassAxisexplicitMemberfalsefalseSubordinate Securitiesus-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldirwt_SubordinateSecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberpureStandardhttp://www.xbrl.org/2003/instancepure0iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Residential | Subordinate Securities72true 3us-gaap_InvestmentHoldingsLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Investment Holdings [Line Items]73false 4rwt_AvailableForSaleSecuritiesCreditReserverwt_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse9600000096000000USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse9600000096000000USD$falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryBalance of credit reserve on available-for-sale securities.No definition available.false2Credit reserve74false 4rwt_LoansUnderlyingrwt_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse1600000000016000000000USD$falsetruefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse1600000000016000000000USD$falsetruefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThe carrying value of loans underlying the security class as of the balance sheet date.No definition available.false2Loans underlying75false 4rwt_DelinquencyRatesrwt_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truetruefalse0.04180.0418falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truetruefalse0.04180.0418falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalsenum:percentItemTypepureDelinquency RatesNo definition available.false0Percentage of outstanding loan serious delinquenciesfalseReal Estate Securities - Additional Information (Detail) (USD $)NoRoundingUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.redwoodtrust.com/taxonomy/role/DisclosureRealEstateSecuritiesAdditionalInformation675