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Business Purpose Loans - Activity and Characteristics of Business Purpose Loans (Details) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2021 USD ($) loan | Dec. 31, 2021 USD ($) loan | Dec. 31, 2020 USD ($) loan | Dec. 31, 2019 USD ($)
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Purchases of held-for-sale loans |  | $ 13,188,434 | $ 4,431,468 | $ 5,823,547
Principal balance of loans sold to third parties |  | 60,667 | 27,210 | 84,303
Transfers from loans held-for-sale to loans held-for-investment |  | 5,026,723 | 1,868,656 | 1,801,560
Transfers from loans held-for-investment to loans held-for-sale |  | $ 92,400 | 64,520 | 22,808
Amount of investments with original maturities of of 30 years (as a percent) |  | 2.00% |  |
Transfers from residential loans to real estate owned |  | $ 40,038 | 14,229 | $ 8,609
Transfers to REO |  | $ 40,038 | 14,119 |
LIBOR |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Variable rate (as a percent) |  | 75.00% |  |
Fixed Rate |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Variable rate (as a percent) |  | 25.00% |  |
CAFL(1) |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Transfers to REO |  | $ 21,129 | $ 6,157 |
Commitment To Fund Residential Bridge Loan |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Other commitment | $ 625,000 | $ 625,000 |  |
Single-family rental loans, held-for-sale |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Number of Loans | loan |  | 245 | 65 |
Unpaid principal balance | 348,232 | $ 348,232 | $ 234,475 |
Single-family rental loans, held-for-sale | Redwood |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Purchases of held-for-sale loans |  | 1,254,913 | 979,696 |
Principal balance of loans acquired (1) |  | 68,804 | 0 |
Principal balance of loans sold to third parties |  | 193,963 | 110,836 |
Transfers from loans held-for-sale to loans held-for-investment |  | 1,116,443 | 1,292,633 |
Transfers from loans held-for-investment to loans held-for-sale |  | 92,455 | 0 |
Gain (loss) on investments |  | 0 | (20,806) |
Loans, at fair value | 358,309 | 358,309 | 245,394 |
Single-family rental loans, held-for-sale | Redwood | Business Purpose Mortgage Banking Activities |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Gain (loss) on investments |  | 63,206 | 81,032 |
Bridge loans held-for-investment |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Purchases of held-for-sale loans |  | 894,908 | 451,554 |
Principal balance of loans acquired (1) |  | 65,315 | 0 |
Principal balance of loans sold to third parties |  | 9,484 | 25,151 |
Gain (loss) on investments |  | 1,483 | $ (10,629) |
Number of Loans | loan |  |  | 1,725 |
Unpaid principal balance |  |  | $ 649,531 |
Loans, at fair value | 666,364 | 666,364 | 641,765 |
Bridge loans held-for-investment | Business Purpose Mortgage Banking Activities |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Gain (loss) on investments |  | $ 7,187 | (2,916) |
Bridge loans held-for-investment | Redwood |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Transfers from loans held-for-sale to loans held-for-investment | 358,884 |  |  |
Transfers from loans held-for-investment to loans held-for-sale | 0 |  |  |
Bridge loans held-for-investment | CAFL(1) |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Number of Loans | loan |  | 1,640 |  |
Unpaid principal balance | 274,617 | $ 274,617 |  |
Business Purpose Loans |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Fee income |  | 34,000 | 19,000 |
Loans, at fair value | 4,790,989 | 4,790,989 | 4,136,353 |
Single-family rental loans held-for-investment | Redwood |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Loans, at fair value | 0 | 0 | 0 |
Single-family rental loans held-for-investment | CAFL(1) |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Gain (loss) on investments |  | $ (158,081) | $ 32,331 |
Number of Loans | loan |  | 1,173 | 1,094 |
Unpaid principal balance | 3,340,949 | $ 3,340,949 | $ 3,017,137 |
Loans, at fair value | $ 3,488,074 | $ 3,488,074 | $ 3,249,194 |
Weighted average coupon rate (as a percent) | 5.17% | 5.17% | 5.44% |
Contract maturities |  | 6 years | 5 years |
Loans held as assets, 90 days or more past due | $ 12,648 | $ 12,648 | $ 24,745 |
Number of loans in foreclosure | loan | 9 | 9 | 10 |
Single-family rental loans held-for-investment | CAFL(1) | Financing Receivables, Equal to Greater than 90 Days Past Due |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Number of loans past due | loan | 18 | 18 | 22 |
Loans held as assets, 90 days or more past due | $ 41,998 | $ 41,998 | $ 61,440 |
Bridge Loans Held For Investment At Fair Value | CAFL(1) |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Gain (loss) on investments |  | $ (1,548) | $ 0 |
Single-Family Rental Loans, Held-For-Sale | Redwood |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Number of Loans | loan |  | 245 | 65 |
Unpaid principal balance | 348,232 | $ 348,232 | $ 234,475 |
Loans, at fair value | $ 358,309 | $ 358,309 | $ 245,394 |
Weighted average coupon rate (as a percent) | 4.73% | 4.73% | 4.84% |
Contract maturities |  | 12 years | 8 years |
Loans held as assets, 90 days or more past due | $ 5,473 | $ 5,473 | $ 0 |
Number of loans in foreclosure | loan | 7 | 7 | 0 |
Loans held as assets amount in foreclosure | $ 4,305 | $ 4,305 | $ 0 |
Single-Family Rental Loans, Held-For-Sale | Redwood | Loans Pledged As Collateral, Short Term Debt |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Gain (loss) on investments |  | 75,873 | 34,098 |
Single-Family Rental Loans, Held-For-Sale | Redwood | Loans Pledged As Collateral, Long Term debt |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Gain (loss) on investments |  | 244,703 | 154,774 |
Single-Family Rental Loans, Held-For-Sale | Redwood | Financing Receivables, Equal to Greater than 90 Days Past Due |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Loans, at fair value | $ 4,238 | $ 4,238 | $ 6,143 |
Number of loans past due | loan | 6 | 6 | 10 |
Loans held as assets, 90 days or more past due | $ 5,384 | $ 5,384 | $ 7,127 |
Business Purpose Bridge Loans |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Number of Loans | loan |  | 1,134 | 1,725 |
Unpaid principal balance | 670,392 | $ 670,392 | $ 649,532 |
Loans, at fair value | $ 666,364 | $ 666,364 | $ 641,765 |
Weighted average coupon rate (as a percent) | 6.91% | 6.91% | 8.09% |
Contract maturities |  | 1 year | 1 year |
Loans held as assets, 90 days or more past due | $ 18,043 | $ 18,043 | $ 38,552 |
Number of loans in foreclosure | loan | 28 | 28 | 25 |
Loans held as assets amount in foreclosure | $ 14,257 | $ 14,257 | $ 33,066 |
Business Purpose Bridge Loans | Loans Pledged As Collateral, Short Term Debt |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Gain (loss) on investments |  | 91,814 | 92,931 |
Business Purpose Bridge Loans | Loans Pledged As Collateral, Long Term debt |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Gain (loss) on investments |  | 554,597 | 544,151 |
Business Purpose Bridge Loans | Financing Receivables, Equal to Greater than 90 Days Past Due |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Loans, at fair value | $ 14,218 | $ 14,218 | $ 33,605 |
Number of loans past due | loan | 31 | 31 | 31 |
Loans held as assets, 90 days or more past due | $ 18,032 | $ 18,032 | $ 39,415 |
Business Purpose Bridge Loans | CAFL(1) |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Number of Loans | loan |  | 1,640 | 0 |
Unpaid principal balance | 274,617 | $ 274,617 | $ 0 |
Loans, at fair value | $ 278,242 | $ 278,242 | $ 0 |
Weighted average coupon rate (as a percent) | 7.05% | 7.05% | 0.00% |
Contract maturities |  | 1 year |  |
Loans held as assets, 90 days or more past due | $ 0 | $ 0 | $ 0 |
Number of loans in foreclosure | loan | 0 | 0 | 0 |
Loans held as assets amount in foreclosure | $ 0 | $ 0 | $ 0 |
Business Purpose Bridge Loans | CAFL(1) | Financing Receivables, Equal to Greater than 90 Days Past Due |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Loans, at fair value | $ 0 | $ 0 | $ 0 |
Number of loans past due | loan | 0 | 0 | 0 |
Loans held as assets, 90 days or more past due | $ 0 | $ 0 | $ 0 |
Bridge Loans | Minimum |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Original maturity (in months) |  | 6 months |  |
Bridge Loans | Maximum |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Original maturity (in months) |  | 24 months |  |

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