Fair Value Disclosures [Abstract] Carrying Values and Fair Values of Assets and Liabilities Fair Value, by Balance Sheet Grouping [Table Text Block] Assets and Liabilities Measured at Fair Value on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Changes in Level 3 Assets and Liabilities Measured at Fair Value on Recurring Basis Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Portion of Net Gains (Losses) Attributable to Level 3 Assets and Liabilities Still Held and Included in Net Income Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Table Text Block] Assets and Liabilities Measured at Fair Value on Non-Recurring Basis Fair Value Measurements, Nonrecurring [Table Text Block] Market Valuation Gains and Losses, Net Schedule Of Market Valuation Adjustments Included In Earnings [Table Text Block] Tabular disclosure for the total amount of market valuation adjustments for the period which are included in earnings. Quantitative Information about Significant Unobservable Inputs Used in Valuation of Level 3 Assets and Liabilities Measured at Fair Value Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Receivables [Abstract] SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate Schedule [Table] SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate Schedule [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Residential loans Residential Mortgage [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Redwood Redwood Trust Inc. [Member] Redwood Trust Inc. [Member] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Legacy Sequoia Legacy Sequoia Securitization Entities [Member] Legacy Sequoia Securitization Entities [Member] Sequoia Choice Sequoia Choice Securitization Entities [Member] Sequoia Choice Securitization Entities [Member] Class of Financing Receivable, Type [Axis] Class of Financing Receivable, Type [Axis] Class of Financing Receivable, Type [Domain] Class of Financing Receivable, Type [Domain] Residential Loans Held For Sale Residential Loans Held For Sale [Member] Residential Loans Held For Sale [Member] Residential Loans Residential Loans at Fair Value [Member] Residential Loans at Fair Value [Member] Residential loans, at lower of cost or fair value Residential Loans at Lower of Cost or Fair Value [Member] Residential Loans at Lower of Cost or Fair Value [Member] Residential Loans Held For Investment at Fair Value Residential Loans Held For Investment At Fair Value [Member] Residential Loans Held For Investment At Fair Value [Member] SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Loan Type [Axis] SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Loan Type [Axis] SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Loan Type [Domain] SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Loan Type [Domain] Jumbo Loans Jumbo Loan [Member] Jumbo Loan [Member] SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] Residential loans Loans and Leases Receivable, Net Amount Segment Reporting [Abstract] Segment Information Segment Reporting Disclosure [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative [Table] Derivative [Table] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Derivative Assets Derivative Financial Instruments, Assets [Member] Liability Class [Axis] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Derivative Liabilities Derivative Financial Instruments, Liabilities [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest rate swaps Interest Rate Swap [Member] TBAs TBA Contracts [Member] TBA Contracts [Member] Futures Future [Member] Swaptions Interest Rate Swaption [Member] Loan purchase commitments Loan Purchase Commitments [Member] Loan forward sale commitments Forward Sales Commitments [Member] Forward Sales Commitments [Member] Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Cash Flow Hedging Cash Flow Hedging [Member] Derivative [Line Items] Derivative [Line Items] Fair Value Derivative, Fair Value, Net Notional Amount Derivative, Notional Amount Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Investments, Debt and Equity Securities [Abstract] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Investment Securities Class [Axis] Investment Securities Class [Axis] Investment Securities Class [Domain] Investment Securities Class [Domain] Prime Real Estate Securities, Prime [Member] Real Estate Securities, Prime [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] Prepayment rates Available For Sale Securities In Unrealized Loss Positions Qualitative Disclosure Prepayment Rates This item represents a significant valuation assumption on prepayment rates, represented as a percentage, which was considered as one of the potential factors in reaching a conclusion that the available-for-sale investments are not other-than-temporarily impaired. Projected losses Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Other, Default Rate Investment Holdings [Table] Investment Holdings [Table] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Senior IO Securities Senior Securities [Member] Senior Securities [Member] Subordinate Securities Subordinate Securities [Member] Subordinate Securities [Member] Mezzanine Real Estate Securities, Prime Mezzanine [Member] Real Estate Securities, Prime Mezzanine [Member] Subordinate Real Estate Securities, Prime Subordinate [Member] Real Estate Securities, Prime Subordinate [Member] Investment Holdings [Line Items] Investment Holdings [Line Items] Available-for-sale securities Available-for-sale Securities Sequoia securities Sequoia Securities [Member] Sequoia Securities [Member] Interest-only Senior Trading Securities Interest Only Senior Trading Securities [Member] Interest Only Senior Trading Securities [Member] Trading securities Trading Securities1 [Member] Trading Securities [Member] CRT securities Credit Risk Transfer (CRT) Securities [Member] Credit Risk Transfer (CRT) Securities [Member] Other third party securities Other Third Party Securities [Member] Other Third Party Securities [Member] Third-party multifamily mortgage-backed securities Third Party Multifamily Mortgage-backed Securities [Member] Third Party Multifamily Mortgage-backed Securities [Member] Residential Residential Mortgage Backed Securities [Member] Collateral [Axis] Collateral [Axis] Collateral [Domain] Collateral [Domain] Residential Subordinate Securities Residential Subordinate Securities [Member] Residential Subordinate Securities [Member] Mezzanine Securities Mezzanine Securities [Member] Mezzanine Securities [Member] AFS securities retained, at fair value Available-for-sale Securities [Member] Certificated Servicing Strips Certificated Servicing Strips [Member] Certificated Servicing Strips [Member] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Net Unrealized Gains on Available-for-Sale Securities Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Trading securities pledged as collateral Debt Securities, Trading, Restricted Debt securities, trading Debt Securities, Trading Unpaid principal balance Investment Owned, Balance, Principal Amount Trading securities Debt Securities, Trading, and Equity Securities, FV-NI Trading securities acquired Payments to Acquire Trading Securities Held-for-investment Trading securities sold Proceeds from Sale of Debt and Equity Securities, FV-NI, Held-for-investment Increase (decrease) in valuation of trading securities Increase (Decrease) in Debt Securities, Trading, and Equity Securities, FV-NI Securities pledged as collateral Debt Securities, Available-for-sale, Restricted Available-for-sale securities purchased Payments to Acquire Available-for-sale Securities Available-for-sale securities sold Proceeds from Sale of Available-for-sale Securities Net realized gains on AFS securities Available-for-sale Securities, Gross Realized Gain (Loss) Marketable securities, less than five years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost Marketable securities, due from five to ten years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost Number of AFS securities (in investments) Number Of Available for Sale Securities Number Of Available for Sale Securities Number of securities in unrealized loss position (in investments) Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Number of securities in a continuous unrealized loss position for twelve consecutive months or longer (in investments) Number of Securities, Continuous Unrealized Loss Position More Than Twelve Months Number of Securities, Continuous Unrealized Loss Position More Than Twelve Months Gross unrealized losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Other than temporary impairment Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net Investment fair value changes, net Unrealized Gain (Loss) on Investments Other than temporary impairment recognized in AOCI Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, before Tax, Including Portion Attributable to Noncontrolling Interest Debt Disclosure [Abstract] Asset-Backed Securities Issued Schedule of Asset Backed Securities [Table Text Block] Tabular disclosure of information pertaining to asset backed securities, including but not limited to identification of components, terms, features, and other information necessary to a fair presentation. Accrued Interest Payable on Asset-Backed Securities Issued Schedule Of Interest Payable On Asset-Backed Securities Issued [Table Text Block] Schedule Of Interest Payable On Asset-Backed Securities Issued [Table Text Block] Collateral for ABS Issued Schedule Of Collateral For Asset Backed Securities [Table Text Block] Tabular disclosure of the collateral for asset backed securities. Equity [Abstract] Stockholders Equity Note [Table] Stockholders Equity Note [Table] Stockholders Equity Note [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Common Stock Common Stock [Member] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Equity awards Stock Compensation Plan [Member] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] Share Repurchase Plan, February 2016 Share Repurchase Plan, February 2016 [Member] Share Repurchase Plan, February 2016 [Member] Share Repurchase Plan, February 2018 Share Repurchase Program, February 2018 [Member] Share Repurchase Program, February 2018 [Member] Stockholders Equity Note [Line Items] Stockholders Equity Note [Line Items] Stockholders Equity Note [Line Items] Issuance of common stock (in shares) Stock Issued During Period, Shares, New Issues Net proceeds from issuance of common stock Proceeds from Issuance of Common Stock Securities excluded in the calculation of diluted earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Common stock authorized to repurchase by Board Stock Repurchase Program, Authorized Amount Shares repurchased pursuant to authorization (in shares) Stock Repurchased During Period, Shares Share repurchases Stock Repurchased During Period, Value Available authorization remaining for repurchase Stock Repurchase Program, Remaining Authorized Repurchase Amount Increase in authorized repurchase amount Stock Repurchase Program, Increase In Authorized Repurchase Amount Stock Repurchase Program, Increase In Authorized Repurchase Amount Document And Entity Information [Abstract] Document And Entity Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Emerging Growth Company Entity Emerging Growth Company Entity Small Business Entity Small Business Real Estate Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Short-Term Debt Short-term Debt [Text Block] Basic Earnings per Common Share: Earnings Per Share, Basic [Abstract] Net income attributable to Redwood Net Income (Loss) Attributable to Parent Less: Dividends and undistributed earnings allocated to participating securities Participating Securities, Distributed and Undistributed Earnings (Loss), Basic Net income allocated to common shareholders Net Income (Loss) Available to Common Stockholders, Basic Basic weighted average common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Basic earnings per common share (in dollars per share) Earnings Per Share, Basic Earnings Per Share, Diluted [Abstract] Earnings Per Share, Diluted [Abstract] Less: Dividends and undistributed earnings allocated to participating securities Participating Securities, Distributed and Undistributed Earnings (Loss), Diluted Add back: Interest expense on convertible notes for the period, net of tax Interest on Convertible Debt, Net of Tax Net income allocated to common shareholders Net Income (Loss) Available to Common Stockholders, Diluted Net effect of dilutive equity awards (in shares) Weighted Average Number Diluted Shares Outstanding Adjustment Net effect of assumed convertible notes conversion to common shares (in shares) Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities Diluted weighted average common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Diluted earnings per common share (in dollars per share) Earnings Per Share, Diluted Classifications and Carrying Value of Loans Carrying Value Of Loans [Table Text Block] Tabular disclosure of the net carrying value for loans by entity as of the balance sheet date. Organization, Consolidation and Presentation of Financial Statements [Abstract] Assets and Liabilities of Consolidated VIEs Schedule of Variable Interest Entities [Table Text Block] Securitization Activity Related to Unconsolidated Variable Interest Entity's Sponsored by Redwood Schedule of Gain (Loss) on Securitizations or Asset-backed Financing Arrangements of Financial Assets Accounted for as Sale [Table Text Block] Cash Flows Related to Unconsolidated Variable Interest Entity's Sponsored by Redwood Cash Flows between Transferee and Transferor Current Period [Table Text Block] Cash Flows between a transferor and a transferee attributable to transferred assets related to either a securitization 0r asset-backed financing arrangement in which the transferor has continuing involvement with the transferred financial assets underlying the transaction (including, but not limited to, servicing, recourse, and restrictions on transferor's interests in the transferred financial assets). Assumptions Related to Assets Retained from Unconsolidated Variable Interest Entity's Sponsored by Redwood Schedule of Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Table Text Block] Unconsolidated Variable Interest Entity's Sponsored by Redwood Qualitative and Quantitative Information, Transferor's Continuing Involvement [Table Text Block] Key Assumptions and Sensitivity Analysis for Assets Retained from Unconsolidated Variable Interest Entity's Sponsored by Redwood Schedule of Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets [Table Text Block] Schedule of Third-Party Sponsored VIE Summary Schedule of Third-Party Sponsored VIE Summary [Table Text Block] Schedule of Third-Party Sponsored VIE Summary [Table Text Block] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Carrying Value Reported Value Measurement [Member] Fair Value Estimate of Fair Value Measurement [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Assets Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Loans, held-for-sale Loans Held-for-sale, Fair Value Disclosure Loans receivable, fair value Loans Receivable, Fair Value Disclosure Business purpose loans Business Purpose Loans, Fair Value Disclosure Business Purpose Loans, Fair Value Disclosure Multifamily loans Multifamily Loans, Fair Value Disclosure Multifamily Loans, Fair Value Disclosure Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Restricted cash Restricted Cash and Cash Equivalents, Fair Value Disclosure Restricted Cash and Cash Equivalents, Fair Value Disclosure Accrued interest receivable Interest Receivable, Fair Value Disclosure Interest Receivable, Fair Value Disclosure Derivative assets Derivative Asset MSRs Servicing Asset at Fair Value, Amount REO Other Assets, Fair Value Disclosure Margin receivable Accounts Receivable, Fair Value Disclosure FHLBC stock Investment in Federal Home Loan Bank Stock, Fair Value Disclosure Guarantee asset Guarantees Asset, Fair Value Disclosure Guarantees Asset, Fair Value Disclosure Pledged collateral Pledged Assets Separately Reported, Other Assets Pledged as Collateral, at Fair Value Participation in loan warehouse facility Participation In Loan Warehouse Facility, Fair Value Disclosure Participation In Loan Warehouse Facility, Fair Value Disclosure Liabilities Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Short-term debt Short-term Debt, Fair Value Accrued interest payable Interest Payable, Fair Value Disclosure Interest Payable, Fair Value Disclosure Margin payable Margin Payable, Fair Value Disclosure Margin Payable, Fair Value Disclosure Guarantee obligation Guarantees, Fair Value Disclosure Derivative liabilities Derivative Liability ABS issued at fair value, net Debt Instrument, Fair Value Disclosure FHLBC long-term borrowings Federal Home Loan Bank Borrowings, Fair Value Disclosure Convertible notes, net Convertible Debt, Fair Value Disclosures Trust preferred securities and subordinated notes, net Trust Preferred Securities And Subordinated Notes, Net, Fair Value Disclosure Trust Preferred Securities And Subordinated Notes, Net, Fair Value Disclosure Commitments and Contingencies Disclosure [Abstract] 2018 (3 months) Operating Leases, Future Minimum Payments, Remainder of Fiscal Year 2019 Operating Leases, Future Minimum Payments, Due in Two Years 2020 Operating Leases, Future Minimum Payments, Due in Three Years 2021 Operating Leases, Future Minimum Payments, Due in Four Years 2022 and thereafter Operating Leases, Future Minimum Payments, Due In Five Years And Thereafter Operating Leases, Future Minimum Payments, Due In Five Years And Thereafter Total Operating Leases, Future Minimum Payments Due Financial Instruments Owned and Pledged as Collateral [Table] Financial Instruments Owned and Pledged as Collateral [Table] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Freddie Mac K-Series Freddie Mac K-Series Securitization Entities [Member] Freddie Mac K-Series Securitization Entities [Member] Residential loans Residential Loans [Member] Residential Loans [Member] Multifamily loans, held-for-investment, at fair value Multifamily Loans [Member] Multifamily Loans [Member] Restricted cash Cash and Cash Equivalents [Domain] Accrued interest receivable Interest Receivable [Member] Interest Receivable [Member] REO Other Real Estate Owned [Member] Other Real Estate Owned [Member] Financial Instruments Owned and Pledged as Collateral [Line Items] Financial Instruments Owned and Pledged as Collateral [Line Items] Collateral for ABS Issued Collateral for Asset Backed Securities Issued The carrying value of collateral as of the balance sheet date for the asset-backed securities issued. Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments Operating Segments [Member] Corporate/Other Corporate, Non-Segment [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Investment Portfolio Residential Investments [Member] Residential Investments [Member] Mortgage Banking Residential Mortgage Banking [Member] Residential Mortgage Banking [Member] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Domain] Financing Receivable Portfolio Segment [Domain] Residential loans Residential Portfolio Segment [Member] Business purpose loans, at fair value Business Purpose Loans [Member] Business Purpose Loans [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Loans, at fair value Real estate securities Marketable Securities Total assets Assets Principles of Consolidation Variable Interest Entity Disclosure [Text Block] Interest income Interest and Dividend Income, Operating Interest expense Interest Expense Net Interest Income Interest Income (Expense), Net Non-interest Income Noninterest Income [Abstract] Mortgage banking activities, net Mortgage Banking Activities, Net The net income attributable to mortgage banking activities. This includes market valuations related to residential and commercial loans, Sequoia IOs, and mortgage banking derivatives, as well as realized gains or losses associated with mortgage loan sales. Investment fair value changes, net Other income, net Other Income Realized gains, net Realized Investment Gains (Losses) Total non-interest income, net Noninterest Income Direct operating expenses Operating Expenses Provision for income taxes Income Tax Expense (Benefit) Net Income Non-cash amortization income (expense), net Amortization Fair Value Measurement Inputs and Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] Residential Senior Securities Residential Senior Securities [Member] Residential Senior Securities [Member] Mortgage servicing rights Mortgage Servicing Rights [Member] Mortgage Servicing Rights [Member] Real estate securities Real Estate Securities [Member] Real Estate Securities [Member] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Fair value option elected aggregate carrying amount, asset Fair Value, Option, Assets, Aggregate Carrying Amount During Period Fair Value, Option, Assets, Aggregate Carrying Amount During Period Dealer marks of securities (as a percent) Percentage of Dealer Quotes Received on Securities Percentage of Third-party Dealer Quotes Received on Securities. Carrying value for which dealer quotes have been received (as a percent) Percentage of Carrying Value for Which Dealer Quotes Were Received on Securities Percentage of Carrying Value for Which Dealer Quotes Were Received on Securities Difference of internal valuation than dealer marks (as a percent) Percentage Difference Of Internal Valuation Than Dealer Marks Percentage Difference Of Internal Valuation Than Dealer Marks Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Mortgage Banking Activities, Net Mortgage Banking Activities [Member] Mortgage Banking Activities [Member] Investment Fair Value Changes, Net Investment Activities [Member] Investment Activities [Member] Other Income, Net Mortgage Servicing Rights Income (Loss), Including Risk Management Derivatives [Member] Mortgage Servicing Rights Income (Loss), Including Risk Management Derivatives [Member] Single-family rental loans held-for-sale, at fair value Single-Family Residential Loans Held-for-sale at Fair Value [Member] Single-Family Residential Loans Held-for-sale at Fair Value [Member] Residential loan purchase and forward sale commitments Risk management derivatives, net Price Risk Derivative [Member] Residential loans held-for-investment, at Redwood Residential Loans Held for Investment [Member] Residential Loans Held for Investment [Member] Fix-and-flip loans held-for-investment Fix And Flip Loans Held-for-investment [Member] Fix And Flip Loans Held-for-investment [Member] Valuation adjustments on commercial loans held-for-sale Commercial Loans Held For Investment [Member] Commercial Loans Held For Investment [Member] Risk-sharing investments Risk Sharing Investments [Member] Risk Sharing Investments [Member] Impairments on AFS securities Impaired Securities [Member] Impaired Securities [Member] MSRs Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Market valuations gains and losses, net Increase (Decrease) in Fair Value Adjustments on Assets Increase (Decrease) in Fair Value Adjustments on Assets Total other income, net Mortgage Servicing Rights Income (Loss), Net Includes income (loss) from mortgage banking servicing real estate mortgages, net of subservicing costs, and market valuation changes of MSRs held at fair value. Total Market Valuation Gains, Net Market Valuation Adjustments, Net The aggregate net change in market value for certain assets and liabilities that was included in earnings for the period. This includes changes in market values for assets and liabilities accounted for at fair value, as well as the credit portion of other-than-temporary impairments on securities available for sale, impairments on loans held-for-sale and real estate owned. Short-Term Debt Facilities Schedule of Short-term Debt [Table Text Block] Short-Term Debt by Collateral Type and Remaining Maturities Schedule of Maturities of Debt Disclosure [Table Text Block] Schedule of Maturities of Debt Disclosure. Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Equity Compensation Plans Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Subsegments [Axis] Subsegments [Axis] Subsegments [Domain] Subsegments [Domain] Legacy Consolidated VIEs Legacy Consolidated Variable Interest Entities [Member] Legacy Consolidated Variable Interest Entities [Member] Other Other Subsegments [Member] Other Subsegments [Member] Other income Other Nonoperating Income (Expense) Net Income Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Asset-backed securities issued Asset-backed Securities [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Amortization of debt issuance costs Amortization of Debt Issuance Costs Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Variable Interest Entity, Not Primary Beneficiary Variable Interest Entity, Not Primary Beneficiary [Member] Interest-only, senior and subordinate securities, classified as trading Interest Only Strip And Senior Securities [Member] Interest Only Strip And Senior Securities [Member] Subordinate securities, classified as AFS Senior and Subordinated Securities [Member] Senior and Subordinated Securities [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] On-balance sheet assets, at fair value: Assets, Fair Value Disclosure [Abstract] Securities Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets Maximum loss exposure Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Assets transferred: Continuing Involvement with Transferred Financial Assets, Amount Outstanding [Abstract] Principal balance of loans outstanding Continuing Involvement with Derecognized Transferred Financial Assets, Amount Outstanding Principal balance of loans 30 days delinquent Derecognized Assets, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together, Delinquent Amount at End of Period Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Residential loans, held-for-sale, at fair value Residential loans, held-for-investment, at fair value Residential Loans Held For Investment At Fair Value, Including Loans At Historical Cost [Member] Residential Loans Held For Investment At Fair Value, Including Loans At Historical Cost [Member] Statement [Line Items] Statement [Line Items] ASSETS Assets [Abstract] Real estate securities, at fair value Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Restricted cash Restricted Cash and Cash Equivalents Accrued interest receivable Interest Receivable Other assets Other Assets Total Assets LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Liabilities Liabilities [Abstract] Short-term debt Short-term Debt Accrued interest payable Interest Payable Accrued expenses and other liabilities Accrued Liabilities Asset-backed securities issued, at fair value Secured Debt Long-term debt, net Long-term Debt Total liabilities Liabilities Equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Common stock, par value $0.01 per share, 180,000,000 shares authorized; 82,930,281 and 76,599,972 issued and outstanding Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Cumulative earnings Retained Earnings (Accumulated Deficit) Cumulative distributions to stockholders Cumulative Dividends Total equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total Liabilities and Equity Liabilities and Equity Mortgage Banking [Abstract] Residential Mortgage Banking Activities Residential Mortgage Banking Activities [Member] Residential Mortgage Banking Activities [Member] Residential loans, at fair value Single-family rental loans, held-for-sale at fair value Single-Family Rental Loans, Held-For-Sale At Fair Value [Member] Single-Family Rental Loans, Held-For-Sale At Fair Value [Member] Changes in fair value of assets Risk management derivatives Increase (Decrease) in Fair Value of Price Risk Fair Value Hedging Instruments Mortgage banking activities, net Variable Interest Entity, Primary Beneficiary Variable Interest Entity, Primary Beneficiary [Member] Estimated fair value of investments Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net Number of securitization entities to which asset transferred (in entities) Number of Securitization Entities to which Asset Transferred Number of Securitization Entities to which Asset Transferred Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract] Margin payable Margin Payable Margin Payable Accrued compensation Employee-related Liabilities Guarantee obligations Guaranty Liabilities Deferred tax liabilities Deferred Income Tax Liabilities, Net Residential loan and MSR repurchase reserve Mortgage Loan On Real Estate, Repurchase Reserve Mortgage Loan On Real Estate, Repurchase Reserve Unsettled trades Unsettled Trades Unsettled Trades Accrued income taxes payable Taxes Payable Legal reserve Estimated Litigation Liability Other Other Liabilities, Miscellaneous Other Liabilities, Miscellaneous Total Accrued Expenses and Other Liabilities Trading securities Risk management derivatives, net Commercial loan Commercial Loan [Member] REO Real Estate Investment [Member] Senior Subordinate Assets Mortgage Banking Activities, Net Mortgage Banking And Investing Activities Disclosure [Text Block] Mortgage Banking And Investing Activities Disclosure [Text Block] Accounting Policies [Abstract] Offsetting Asset and Liabilities [Table] Offsetting Asset and Liabilities [Table] Offsetting Asset and Liabilities [Table] Interest Rate Agreement, TBAs, And Futures Interest Rate Agreement, TBAs, And Futures [Member] Interest Rate Agreement, TBAs, And Futures [Member] Interest rate agreements Loan warehouse debt Warehouse Agreement Borrowings [Member] Security repurchase agreements Repurchase Agreements [Member] Offsetting Asset and Liabilities [Line Items] Offsetting Asset and Liabilities [Line Items] Offsetting Asset and Liabilities [Line Items] Future lease commitments with expiration date Loans held-for-investment, term Loans Held-For-Investment, Term Loans Held-For-Investment, Term Gross Amounts of Recognized Assets Derivative Asset, Fair Value, Gross Asset Gross Amounts Offset in Consolidated Balance Sheet Derivative Asset, Fair Value, Gross Liability Net Amounts of Assets Presented in Consolidated Balance Sheet Gross Amounts Not Offset in Consolidated Balance Sheet - Financial Instruments Derivative, Collateral, Obligation to Return Securities Gross Amounts Not Offset in Consolidated Balance Sheet, Cash Collateral Pledged Derivative, Collateral, Obligation to Return Cash Net Amount Derivative Asset, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election Gross Amounts of Recognized Liabilities Derivative Liability, Fair Value, Gross Liability Gross Amounts of Recognized Liabilities - Under Repurchase Agreements Securities Sold under Agreements to Repurchase, Gross Gross Amounts of Recognized Liabilities, Including Assets Under Repurchase Agreements Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Gross Gross Amounts Offset in Consolidated Balance Sheet Derivative Liability, Fair Value, Gross Asset Gross Amounts Offset in Consolidated Balance Sheet - Under Repurchase Agreement Securities Sold under Agreements to Repurchase, Asset Gross Amounts Offset in Consolidated Balance Sheet Including Assets Under Repurchase Agreement Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Asset Net Amounts of Liabilities Presented in Consolidated Balance Sheet Net Amounts of Liabilities Presented in Consolidated Balance Sheet - Under Repurchase Agreement Securities Sold under Agreements to Repurchase Net Amounts of Liabilities Presented in Consolidated Balance Sheet Including Assets Under Repurchase Agreement Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned Gross Amounts Not Offset in Consolidated Balance Sheet, Financial Instruments Derivative, Collateral, Right to Reclaim Securities Gross Amounts Not Offset in Consolidated Balance Sheet, Financial Instruments - Under Repurchase Agreement Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities Gross Amounts Not Offset in Consolidated Balance Sheet, Financial Instruments Including Assets Under Repurchase Agreement Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Collateral, Right to Reclaim Securities Gross Amounts Not Offset in Consolidated Balance Sheet, Cash Collateral Pledged Derivative, Collateral, Right to Reclaim Cash Gross Amounts Not Offset in Consolidated Balance Sheet, Cash Collateral Pledged - Under Repurchase Agreement Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Cash Gross Amounts Not Offset in Consolidated Balance Sheet, Cash Collateral Pledged Including Assets Under Repurchase Agreement Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Collateral, Right to Reclaim Cash Net Amount Derivative Liability, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election Net Amount - Under Repurchase Agreement Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral Net Amount Including Assets Under Repurchase Agreement Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Amount Offset Against Collateral Schedule of Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Table] Schedule of Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Table] Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items] Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items] Prepayment rates Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities, Prepayment Speed Discount rates Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities, Discount Rate Credit loss assumptions Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities, Expected Credit Losses Mortgage Banking Activities Income and Expense Attributable To Mortgage Banking Activities [Table Text Block] Tabular disclosure of the components of mortgage banking activities, net. This includes market valuations related to residential and commercial loans, retained Sequoia IOs, and mortgage banking derivatives, as well as realized gains or losses associated with residential and commercial loan sales and securitizations. Investment Secondary Categorization [Axis] Investment Secondary Categorization [Axis] Investments by Secondary Categorization [Domain] Investments by Secondary Categorization [Domain] Contractual maturities of over five years Maturity over Five Years [Member] Maturity over Five Years [Member] Contractual maturities of ABS (in years) Long Term Marketable Securities Maturities Term Long Term Marketable Securities Maturities Term Federal Home Loan Bank Branch [Axis] Federal Home Loan Bank Branch [Axis] Federal Home Loan Bank Branch [Domain] Federal Home Loan Bank Branch [Domain] FHLB Chicago Federal Home Loan Bank of Chicago [Member] FHLB Member Subsidiary FHLB Subsidiary [Member] FHLB Subsidiary [Member] Held-for-sale residential loans Residential Real Estate Residential Real Estate [Member] Restricted cash Restricted Cash [Member] Restricted Cash [Member] Senior Notes Due 2024 Senior Notes Due 2024 [Member] Senior Notes Due 2024 [Member] Senior Notes Due 2023 Senior Notes Due 2023 [Member] Senior Notes Due 2023 [Member] Exchangeable Senior Notes Due 2019 Exchangeable Senior Notes Due 2019 [Member] Exchangeable Senior Notes Due 2019 [Member] Convertible Senior Notes Due 2018 Convertible Senior Notes Due 2018 [Member] Convertible Senior Notes Due 2018 [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Convertible Debt Convertible Debt [Member] Trust Preferred Securities And Subordinated Notes Trust Preferred Securities And Subordinated Notes [Member] Trust Preferred Securities And Subordinated Notes [Member] Trust Preferred Securities Trust Preferred Securities [Member] Trust Preferred Securities [Member] Subordinated Notes Senior Subordinated Notes [Member] Facilities Line of Credit [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Gain (loss) on investments Gain (Loss) on Investments [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] LIBOR London Interbank Offered Rate (LIBOR) [Member] Maximum borrowing limit Line of Credit Facility, Maximum Borrowing Capacity Additional borrowings from FHLBC Proceeds from FHLBank Advance, Investing Activities Transition period for subsidiary to be a FHLB-member (in years) Federal Home Loan Bank, Transition Period Subsidiary To Member Of FHLB Federal Home Loan Bank, Transition Period Subsidiary To Member Of FHLB Existing debt Long-term Line of Credit Federal home loan bank advances outstanding Long-term Federal Home Loan Bank Advances Weighted average interest rate Long-term Debt, Weighted Average Interest Rate, at Point in Time Weighted average maturity (in years) Debt Instrument, Term Federal home loan bank advances, reset period of basis margin (in days) Debt Instrument, Interest Rate Margin Reset Period Debt Instrument, Interest Rate Margin Reset Period Loans pledged as collateral under borrowing agreement with FHLBC Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged Federal home loan bank stock Federal Home Loan Bank Stock Convertible notes Convertible Notes Payable Debt Instrument interest rate Debt Instrument, Interest Rate, Stated Percentage Debt instrument, percent of par Debt Instrument, Percent Of Par Debt Instrument, Percent Of Par Net proceeds from issuance of convertible debt Proceeds from Debt, Net of Issuance Costs Interest expense yield Debt Instrument, Interest Rate During Period Convertible senior notes conversion rate Debt Instrument, Convertible, Conversion Ratio Convertible senior notes conversion per share (in dollars per share) Debt Instrument, Convertible, Conversion Price Accrued interest payable Interest Payable, Current Unamortized debt issuance costs Unamortized Debt Issuance Expense Unamortized discount Debt Instrument, Unamortized Discount Debt instrument maturity year Debt Instrument Maturity Year Debt Instrument Maturity Year Debt instrument redemption date Debt Instrument Redemption Date Debt Instrument Redemption Date Amount of debt repurchased Debt Instrument, Repurchased Face Amount Gain on extinguishment of debt Gain (Loss) on Extinguishment of Debt Unamortized deferred issuance costs Debt Issuance Costs, Net Debt instrument face amount Debt Instrument, Face Amount Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Notional amount Weighted average interest rates, by series Debt, Weighted Average Interest Rate Common stock, par value (usd per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (shares) Common Stock, Shares Authorized Common stock, issued (shares) Common Stock, Shares, Issued Common stock, outstanding (shares) Common Stock, Shares, Outstanding Variable interest held by entity, assets Variable Interest Entity, Consolidated, Carrying Amount, Assets Variable interest held by entity, liabilities Variable Interest Entity, Consolidated, Carrying Amount, Liabilities Convertible notes Convertible Notes Payable, Current Fair Value of Financial Instruments Fair Value Disclosures [Text Block] Financing Receivables, Period Past Due [Axis] Financing Receivables, Period Past Due [Axis] Financing Receivables, Period Past Due [Domain] Financing Receivables, Period Past Due [Domain] Financing Receivables, Equal to Greater than 90 Days Past Due Financing Receivables, Equal to Greater than 90 Days Past Due [Member] Fixed rate residential mortgage Fixed Rate Residential Mortgage [Member] Hybrid or ARM Loans Hybrid Or ARM Loans [Member] Hybrid Or ARM Loans [Member] SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Loan Category [Axis] SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Loan Category [Axis] SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Loan Category [Domain] SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Loan Category [Domain] Originated Between 2013 and 2018 Originated Between Twenty Thirteen And Twenty Eighteen [Member] Originated Between Twenty Thirteen And Twenty Eighteen [Member] Originated 2012 and prior years Originated During Twenty Twelve And Prior Years [Member] Originated During Twenty Twelve And Prior Years [Member] Mortgage servicing rights, at amortized cost Servicing Asset at Amortized Cost Number of loans SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Number of Loans Loan Principal Principal Amount Outstanding on Loans Managed and Securitized or Asset-backed Financing Arrangement Number of loans past due Financing Receivable, Number Of Loans Past Due Financing Receivable, Number Of Loans Past Due Loans held-for-investment, delinquent greater than 90 days Fair Value, Option, Loans Held as Assets, 90 Days or More Past Due Number of loans in foreclosure Financing Receivable, Number Of Loans In Foreclosure Financing Receivable, Number Of Loans In Foreclosure Principal value of loans purchased Principal Balance of Loans Acquired During Period Principal Balance of Loans Acquired During Period Principal balance of loans sold during period Principal Balance of Loans Sold During Period Principal Balance of Loans Sold During Period Gain (loss) on assets measured at fair value on a non-recurring basis Fair Value, Option, Changes in Fair Value, Gain (Loss) Loan pledged as collateral Loans Pledged as Collateral Transfers from loans held-for-sale to loans held-for-investment Transfer of Loans Held-for-sale to Portfolio Loans Transfers from loans held-for-investment to loans held-for-sale Transfer of Portfolio Loans and Leases to Held-for-sale Percentage of loan portfolio originated in year Percentage Of Loan Portfolio Percentage Of Loan Portfolio Weighted average original Fair Isaac Corporation (FICO) score Financing Receivable, Credit Score, FICO, Weighted Average The weighted average FICO score for borrowers at the time loans were originated. Weighted average original loan-to-value (LTV) Financing Receivable, Loan To Value Ratio Financing Receivable, Loan To Value Ratio Percentage of fixed-rate loans Loans Receivable, Percentage Bearing Fixed Interest, Percentage Rate Loans Receivable, Percentage Bearing Fixed Interest, Percentage Rate Weighted average coupon rate Financing Receivables, Weighted Average Interest Rate Financing Receivables, Weighted Average Interest Rate Loans held-for-investment, in foreclosure Fair Value, Option, Loans Held As Assets, Aggregate Amount In Foreclosure Fair Value, Option, Loans Held As Assets, Aggregate Amount In Foreclosure Valuation adjustment gain (loss) SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Period Increase (Decrease) Statement of Stockholders' Equity [Abstract] Additional Paid-In Capital Additional Paid-in Capital [Member] Accumulated Other Comprehensive Income AOCI Attributable to Parent [Member] Cumulative Earnings Retained Earnings [Member] Cumulative Distributions to Stockholders Accumulated Distributions in Excess of Net Income [Member] Increase (Decrease) in Stockholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning balance Stockholders' Equity Attributable to Parent Beginning balance (in shares) Shares, Issued Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Issuance of common stock Stock Issued During Period, Value, New Issues Employee stock purchase and incentive plans Stock Issued During Period, Value, Employee Stock Purchase Plans And Other Incentive Plans Stock Issued During Period, Value, Employee Stock Purchase Plans And Other Incentive Plans Employee stock purchase and incentive plans (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans And Other Incentive Plans Stock Issued During Period, Shares, Employee Stock Purchase Plans And Other Incentive Plans Non-cash equity award compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Share repurchases Share repurchases (in shares) Common dividends declared Dividends, Common Stock Ending balance Ending balance (in shares) Mutlifamily Loans Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Income Tax Disclosure [Abstract] Other Assets and Liabilities Other Assets And Other Liabilities Disclosure [Text Block] Other Assets And Other Liabilities Disclosure Business Purpose Loans Option Indexed to Issuer's Equity [Axis] Option Indexed to Issuer's Equity [Axis] Option Indexed to Issuer's Equity, Type [Domain] Option Indexed to Issuer's Equity, Type [Domain] Sales Put Option [Member] Calls Call Option [Member] Gross realized gains Available-for-sale Securities, Gross Realized Gains Gross realized losses Available-for-sale Securities, Gross Realized Losses Total Realized Gains on Sales and Calls of AFS Securities, net Available-for-sale Securities, Gross Realized Gain (Loss) On Sales And Calls Available-for-sale Securities, Gross Realized Gain (Loss) On Sales And Calls Principal balance Available For Sale Securities Principal Balance Available For Sale Securities Principal Balance Credit reserve Available For Sale Securities Credit Reserve Balance of credit reserve on available-for-sale securities. Unamortized discount, net Available For Sale Securities Unamortized Discounts Premiums Balance of net unamortized discount on available-for-sale securities. Amortized cost Debt Securities, Available-for-sale, Amortized Cost Gross unrealized gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Gross unrealized losses Carrying Value Debt Securities, Available-for-sale Schedule of Servicing Assets at Fair Value [Table] Schedule of Servicing Assets at Fair Value [Table] Servicing Assets at Fair Value [Line Items] Servicing Assets at Fair Value [Line Items] Balance at beginning of period Additions Servicing Asset at Fair Value, Additions Sales Servicing Asset at Fair Value, Disposals Changes in assumptions Asset at Fair Value, Changes in Fair Value Resulting from Changes in Assumptions Other changes Servicing Asset at Fair Value, Other Changes in Fair Value Balance at End of Period Other Income and Expenses [Abstract] Fixed compensation expense Fixed Compensation Expense Fixed Compensation Expense Variable compensation expense Variable Compensation Expense Variable Compensation Expense Equity compensation expense Allocated Share-based Compensation Expense Total compensation expense Labor and Related Expense Systems and consulting Communications and Information Technology Loan acquisition costs Loan Acquisition Costs Loan Acquisition Costs Office costs General and Administrative Expense Accounting and legal Professional Fees Corporate costs Other General Expense Other operating expenses Other Cost and Expense, Operating Total Operating Expenses Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Future Lease Commitments by Year Lessee, Operating Lease, Disclosure [Table Text Block] Investment Fair Value Changes Schedule Of Investments Fair Value Changes, Net [Table Text Block] Schedule Of Investments Fair Value Changes, Net [Table Text Block] Income Statement [Abstract] Interest Income Interest and Dividend Income, Operating [Abstract] Residential loans Interest and Fee Income, Loans, Consumer, Real Estate Business purpose loans Interest and Fee Income, Nonmortgage Loans and Leases Held-for-sale Multifamily loans Interest and Fee Income, Loans Held-for-sale, Mortgages Real estate securities Interest Income, Securities, Mortgage Backed Other interest income Interest Income, Other Total interest income Interest Expense Interest Expense [Abstract] Short-term debt Interest Expense, Short-term Borrowings Asset-backed securities issued Interest Expense, Beneficial Interests Issued by Consolidated Variable Interest Entities Long-term debt Interest Expense, Long-term Debt Total Interest Expense Operating expenses Net Income before Provision for Income Taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Regular dividends declared per common share (in dollars per share) Common Stock, Dividends, Per Share, Declared Basic weighted average shares outstanding (in shares) Diluted weighted average shares outstanding (in shares) Residential Loans Federal statutory rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent State statutory rate, net of Federal tax effect Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Differences in taxable (loss) income from GAAP income Effective Income Tax Rate Reconciliation, Deduction, Percent Change in valuation allowance Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent Dividends paid deduction Effective Income Tax Rate Reconciliation, Deduction, Dividend, Percent Effective Tax Rate Effective Income Tax Rate Reconciliation, Percent Schedule of Short-term Debt [Table] Schedule of Short-term Debt [Table] Fix and flip loan warehouse Fix And Flip Loan Warehouse Facilities [Member] Fix And Flip Loan Warehouse Facilities [Member] Single-family rental loan warehouse Single-Family Rental Loan Warehouse Facilities [Member] Single-Family Rental Loan Warehouse Facilities [Member] Short-term Debt [Line Items] Short-term Debt [Line Items] Collateral amounts Debt Instrument, Collateral Amount Average balance of short-term debt Short-term Debt, Average Outstanding Amount Accrued interest payable on short-term debt Gain (loss) on extinguishment of debt Committed line of credit Line of Credit Facility, Current Borrowing Capacity Fair value of mortgage backed securities securing loan (in excess) Financial Instruments, Owned and Pledged as Collateral, at Fair Value Committed line of credit with financial institutions, outstanding Investment Fair Value Changes, Net Investments Fair Value Changes, Net [Text Block] Investments Fair Value Changes, Net [Text Block] Fair Value, Assets And Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets And Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets And Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] AFS Securities Guarantee Asset Asset Value Guarantees [Member] Asset Value Guarantees [Member] Derivatives ABS Issued Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Assets Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Beginning balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Acquisitions Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Principal paydowns Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Calls, Maturities, Paydowns Principal paydowns, including calls and maturities, that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy. Gains (losses) in net income, net Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Unrealized losses in OCI, net Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Other settlements, net Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Ending balance Liabilities Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Beginning balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Acquisitions Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales Principal paydowns Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Paydowns Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Paydowns Gains (losses) in net income, net Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Unrealized losses in OCI, net Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss) Other settlements, net Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Ending balance Servicing income Contractually Specified Servicing Fees, Amount Cost of sub-servicer Mortgage Servicing Expense Mortgage Servicing Expense Net servicing fee income Contractually Specified Servicing Fee, Late Fee, and Ancillary Fee Earned in Exchange for Servicing Financial Asset Market valuation changes of MSRs Total Net Change In Market Value Related to Mortgage Servicing Rights Total net change in market value related to mortgage servicing rights. Market valuation changes of associated derivatives Market Valuation Changes In Associated Derivatives Market Valuation Changes In Associated Derivatives MSR reversal of provision for repurchases Provision For Mortgage Servicing Rights Repurchases Provision For Mortgage Servicing Rights Repurchases MSR Income, Net Mortgage Servicing Rights Income Including Market Valuation Changes of MSRs Includes income from mortgage banking servicing real estate mortgages, net of subservicing costs, and market valuation changes of MSRs held at fair value. Interest rate contract Interest Rate Contract [Member] Unsecuritized Residential and Commercial Loans Residential and Commercial Loans [Member] Residential and Commercial Loans [Member] Net Unrealized Losses on Interest Rate Agreements Accounted for as Cash Flow Hedges Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] Derivative gain (loss) Derivative, Gain (Loss) on Derivative, Net Net unrealized gain (loss) on interest rate agreements Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Accumulated other comprehensive income Number of counterparties Derivative, Number Of Counterparties Derivative, Number Of Counterparties Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Principles of Consolidation Consolidation, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Balance Sheet Netting Balance Sheet Netting [Policy Text Block] Balance Sheet Netting Components of Other Assets Schedule of Other Assets [Table Text Block] Components of Accrued Expenses and Other Liabilities Accrued Expenses and Other Liabilities [Table Text Block] Accrued Expenses and Other Liabilities [Table Text Block] Activity for Mortgage Servicing Rights Schedule of Servicing Assets at Fair Value [Table Text Block] Components of Mortgage Servicing Rights Income (Loss), net Schedule Of Components Of Mortgage Backed Securities Interest Income [Table Text Block] Schedule Of Components Of Mortgage Backed Securities Interest Income [Table Text Block] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Restricted Stock Restricted Stock [Member] Deferred Stock Units Deferred Stock Units [Member] Deferred Stock Units [Member] Performance Stock Units Performance Shares [Member] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Performance Share Units (PSUs), 2015 and 2017 Performance Share Units (PSUs), 2015 And 2017 [Member] Performance Share Units (PSUs), 2015 And 2017 [Member] Performance Share Units (PSUs), 2017 Performance Share Units (PSUs), 2017 [Member] Performance Share Units (PSUs), 2017 [Member] Performance Share Units (PSUs), 2016 Performance Share Units (PSUs), 2016 [Member] Performance Share Units (PSUs), 2016 [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Shares of common stock available for grant under Redwood's Incentive Plan (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Additional shares authorized under Incentive Plan Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant, Increase Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant, Increase Unrecognized compensation cost Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Weighted average amortization period remaining for equity awards (less than) Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Unvested outstanding stock awards (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Number of stock awards granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Number of stock awards vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Number of stock awards forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Number of stock awards distributed (in shares) Share Based Compensation Arrangement by Share Based Payment Award, Equity Instruments Other Than Options, Distributed in Period Share Based Compensation Arrangement by Share Based Payment Award, Equity Instruments Other Than Options, Distributed in Period Share-based compensation, vesting period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Award vesting rights, percentage Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage TSR, percent Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Total Share Return, Percentage Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Total Share Return, Percentage PSU, weighted average grant date fair value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Fair value, average closing price of common stock, measurement period Share-based Compensation Arrangement By Share-based Payment Award, Fair Value Assumptions, Average Closing Price Of Common Stock, Measurement Period Share-based Compensation Arrangement By Share-based Payment Award, Fair Value Assumptions, Average Closing Price Of Common Stock, Measurement Period Fair value assumptions, expected volatility rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Fair value assumptions, risk free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Fair value, expected dividend rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Shares of common stock to be purchased in aggregate for all employees (in shares) Employee Stock Purchase Plan, Number of Shares Authorized Maximum amount of shares of common stock permitted to be purchased for all employees under the Employee Stock Purchase Plan. Number of shares purchased by employees (in shares) Employee Stock Purchase Plan, Number of Shares Purchased by Employee Amount of shares of common stock purchased by employees under the Employee Stock Purchase Plan in the current period. Unamortized Discount and Designated Credit Reserves Unamortized Discount and Designated Credit Reserves [Roll Forward] Unamortized Discount and Designated Credit Reserves [Roll Forward] Credit Reserve Available For Sale Securities Credit Reserve [Roll Forward] Available For Sale Securities Credit Reserve [Roll Forward] Beginning balance Amortization of net discount Available For Sale Securities Credit Reserve, Amortization of net (Discount) Premium Changes to credit reserve on available-for-sale securities due to the amortization of net discount Realized credit losses Available For Sale Securities Credit Reserve, Realized Credit Gains Losses Changes to the credit reserve on available-for-sale securities due to realized credit losses. Acquisitions Available For Sale Securities Credit Reserve, Acquisitions Changes to the credit reserve on available-for-sale securities due to security acquisitions. Sales, calls, other Available For Sale Securities Credit Reserve, Sales, Calls, Other Changes to the credit reserve on available-for-sale securities due to sales, calls, and other items. Impairments Available for Sale Securities Credit Reserve, Impairments Changes to the credit reserve on available-for-sale securities due to impairments. (Release of) transfers to credit reserves, net Available For Sale Securities Credit Reserve, Transfers to (Release of) Credit Reserves Transfers to or releases of the credit reserve on available-for-sale securities. Ending Balance Unamortized Discount, Net Available For Sale Securities Unamortized Discounts Premiums [Abstract] [Roll Forward] Available For Sale Securities Unamortized Discounts Premiums [Abstract] [Roll Forward] Beginning balance Amortization of net discount Available For Sale Securities Unamortized Discounts Premiums, Amortization of net (discount) premium Changes to the net unamortized discount on available-for-sale securities due to the amortization of net discount. Realized credit losses Available For Sale Securities Unamortized Discounts Premiums, Realized Credit Gains Losses Changes to the net unamortized discount on available-for-sale securities due to realized credit losses. Acquisitions Available For Sale Securities Unamortized Discounts Premiums, Acquisitions Changes to the net unamortized discount on available-for-sale securities due to security acquisitions. Sales, calls, other Available For Sale Securities Unamortized Discounts Premiums, Sales, Calls, Other Changes to the net unamortized discount on available-for-sale securities due to sales, calls, and other items. Impairments Available For Sale Securities Unamortized Discounts Premiums, Impairments Changes to the net unamortized discount on available-for-sale securities due to impairments. (Release of) transfers to credit reserves, net Available For Sale Securities Unamortized Discounts Premiums, Transfers to (Release of) Credit Reserves Transfers to or releases of the credit reserve on available-for-sale securities. Ending Balance Net interest expense on cash flows hedges Interest Expense Cash Flow Hedge Amount of interest expense recognized in earnings on cash flow hedge. Realized net losses reclassified from other comprehensive income Derivative Instruments, Loss Reclassified from Accumulated OCI into Income, Effective Portion Changes to Accumulated Other Comprehensive Income by Component Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Reclassifications out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Basic and Diluted Earnings Per Common Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Investment fair value changes, net Realized gains, net Provision for income taxes Net Income before Provision for Income Taxes Interest expense Impairment losses, investments Other than Temporary Impairment Losses, Investments Certificates with principal balance Certificates With Principal Value [Member] Certificates With Principal Value [Member] Interest-only certificates Interest Only Certificates [Member] Interest Only Certificates [Member] Certificates with principal balance Long-term Debt, Gross Market valuation adjustments New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets Total FHLBC Borrowings Number of series Number of Series Number of Series Equity Compensation Costs by Award Type Schedule of Unrecognized Compensation Cost, Nonvested Awards [Table Text Block] Number of operating segments Number of Operating Segments Purchases of held-for-sale loans Payments to Purchase Loans Held-for-sale Proceeds from sales of held-for-sale loans Proceeds from Sale of Loans Held-for-sale Gain (loss) on investments Gain (Loss) on Investments Weighted-average debt service coverage ratio Financing Receivable, Weighted Average Debt Service Coverage Ratio Financing Receivable, Weighted Average Debt Service Coverage Ratio Unpaid principal balance on delinquent or foreclosure loans Loans And Leases Receivable, Delinquent Or In Foreclosure Loans And Leases Receivable, Delinquent Or In Foreclosure Contract maturities Financing Receivable, Contract Maturities Financing Receivable, Contract Maturities Estimated rehabilitated loan-to-value ratio Financing Receivable, Rehabilitated Loan To Value Ratio Financing Receivable, Rehabilitated Loan To Value Ratio Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Convertible notes, net Convertible Notes Payable [Member] Residential loan warehouse Residential Loan Warehouse [Member] Residential Loan Warehouse [Member] Real estate securities repo Real Estate Securities Repo [Member] Real Estate Securities Repo [Member] Number of Facilities Number of Facilities Number of Facilities Outstanding Balance Limit Weighted Average Interest Rate Short-term Debt, Weighted Average Interest Rate, at Point in Time Weighted Average Days Until Maturity (in days) Debt Instrument Average, Maturity Term Debt Instrument Average, Maturity Term Loss Contingencies [Table] Loss Contingencies [Table] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Forecast Scenario, Forecast [Member] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Guarantee Obligations Guarantee Obligations [Member] Other income Other Income [Member] Mortgage banking and investment activities Mortgage Banking And Investment Activities [Member] Mortgage Banking And Investment Activities [Member] Sequoia Sequoia Securitization Entities [Member] Sequoia Securitization Entities [Member] Loss Contingencies by Name of Plaintiff [Axis] Loss Contingencies by Name of Plaintiff [Axis] Loss Contingencies by Name of Plaintiff [Axis] Loss Contingencies by Name of Plaintiff [Domain] Loss Contingencies by Name of Plaintiff [Domain] Loss Contingencies by Name of Plaintiff [Domain] FHLB Seattle Federal Home Loan Bank of Seattle [Member] Schwab Charles Schwab Corporation [Member] Charles Schwab Corporation [Member] Morgan Stanley & Co. Morgan Stanley And Company [Member] Morgan Stanley And Company [Member] Sequoia Residential Funding Sequoia Residential Funding [Member] Sequoia Residential Funding [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Number of noncancelable leases Operating Leases, Number Of Leases, Noncancelable Operating Leases, Number Of Leases, Noncancelable Operating lease expiration dates Lease Expiration Year