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Residential Whole Loans (Additional Credit Related Information) (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2021 | Jun. 30, 2021 | Mar. 31, 2021 | Sep. 30, 2020 | Jun. 30, 2020 | Mar. 31, 2020 | Sep. 30, 2021 | Dec. 31, 2020
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | $ 105,270 |  |  |  |  |  | $ 105,270 |
2020 | 415,756 |  |  |  |  |  | 415,756 |
2019 | 1,215,425 |  |  |  |  |  | 1,215,425 |
2018 | 546,523 |  |  |  |  |  | 546,523 |
2017 | 59,843 |  |  |  |  |  | 59,843 |
Prior | 689,149 |  |  |  |  |  | 689,149 |
Residential whole loans, total or weighted average | 3,031,966 |  |  |  |  |  | 3,031,966 |
Gross write-offs, 2020 |  |  |  |  |  |  | 0 |
Gross write-offs, 2019 |  |  |  |  |  |  | 1,115 |
Gross write-offs, 2018 |  |  |  |  |  |  | 505 |
Gross write-offs, 2017 |  |  |  |  |  |  | 123 |
Gross write-offs, prior |  |  |  |  |  |  | 406 |
Nine Months Ended September 30, 2021 Gross write-offs | 533 | $ 400 | $ 1,217 | $ 281 | $ 627 | $ 647 | 2,149 |
Net write-offs, 2020 |  |  |  |  |  |  | 0 |
Net write-offs, 2019 |  |  |  |  |  |  | 1,115 |
Net write-offs, 2018 |  |  |  |  |  |  | 505 |
Net write-offs, 2017 |  |  |  |  |  |  | 123 |
Net write-offs |  |  |  |  |  |  | 406 |
Nine Months Ended September 30, 2021 Net write-offs |  |  |  |  |  |  | $ 2,149 |
Ratio Loan-To-Value |  |  |  |  |  |  | 80.00% |
Debt-to-Value Ratio, Less than 80 Percent |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 101,079 |  |  |  |  |  | $ 101,079 |
2020 | 386,874 |  |  |  |  |  | 386,874 |
2019 | 1,193,084 |  |  |  |  |  | 1,193,084 |
2018 | 530,954 |  |  |  |  |  | 530,954 |
2017 | 54,966 |  |  |  |  |  | 54,966 |
Prior | 530,840 |  |  |  |  |  | 530,840 |
Residential whole loans, total or weighted average | 2,797,797 |  |  |  |  |  | 2,797,797 |
Debt-to-Value Ratio, 81 to 100 Percent |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 4,191 |  |  |  |  |  | 4,191 |
2020 | 28,882 |  |  |  |  |  | 28,882 |
2019 | 22,341 |  |  |  |  |  | 22,341 |
2018 | 15,569 |  |  |  |  |  | 15,569 |
2017 | 4,877 |  |  |  |  |  | 4,877 |
Prior | 158,309 |  |  |  |  |  | 158,309 |
Residential whole loans, total or weighted average | 234,169 |  |  |  |  |  | 234,169 |
Non-QM loans |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 76,051 |  |  |  |  |  | 76,051 |
2020 | 350,244 |  |  |  |  |  | 350,244 |
2019 | 786,165 |  |  |  |  |  | 786,165 |
2018 | 422,629 |  |  |  |  |  | 422,629 |
2017 | 43,558 |  |  |  |  |  | 43,558 |
Prior | 4,378 |  |  |  |  |  | 4,378 |
Residential whole loans, total or weighted average | 1,683,025 |  |  |  |  |  | 1,683,025 |
Gross write-offs, 2018 |  |  |  |  |  |  | 37 |
Nine Months Ended September 30, 2021 Gross write-offs |  |  |  |  |  |  | 37 |
Net write-offs, 2018 |  |  |  |  |  |  | 37 |
Nine Months Ended September 30, 2021 Net write-offs |  |  |  |  |  |  | 37 |
Non-QM loans | Debt-to-Value Ratio, Less than 80 Percent |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 71,860 |  |  |  |  |  | 71,860 |
2020 | 321,875 |  |  |  |  |  | 321,875 |
2019 | 770,456 |  |  |  |  |  | 770,456 |
2018 | 407,943 |  |  |  |  |  | 407,943 |
2017 | 40,381 |  |  |  |  |  | 40,381 |
Prior | 4,228 |  |  |  |  |  | 4,228 |
Residential whole loans, total or weighted average | 1,616,743 |  |  |  |  |  | 1,616,743 |
Non-QM loans | Debt-to-Value Ratio, 81 to 100 Percent |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 4,191 |  |  |  |  |  | 4,191 |
2020 | 28,369 |  |  |  |  |  | 28,369 |
2019 | 15,709 |  |  |  |  |  | 15,709 |
2018 | 14,686 |  |  |  |  |  | 14,686 |
2017 | 3,177 |  |  |  |  |  | 3,177 |
Prior | 150 |  |  |  |  |  | 150 |
Residential whole loans, total or weighted average | 66,282 |  |  |  |  |  | 66,282 |
Rehabilitation loans |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 13,717 |  |  |  |  |  | 13,717 |
2020 | 27,910 |  |  |  |  |  | 27,910 |
2019 | 215,844 |  |  |  |  |  | 215,844 |
2018 | 32,024 |  |  |  |  |  | 32,024 |
2017 | 5,127 |  |  |  |  |  | 5,127 |
Prior | 0 |  |  |  |  |  | 0 |
Residential whole loans, total or weighted average | 294,622 |  |  |  |  |  | 294,622 |
Gross write-offs, 2019 |  |  |  |  |  |  | 1,059 |
Gross write-offs, 2018 |  |  |  |  |  |  | 468 |
Gross write-offs, 2017 |  |  |  |  |  |  | 123 |
Nine Months Ended September 30, 2021 Gross write-offs |  |  |  |  |  |  | 1,650 |
Net write-offs, 2019 |  |  |  |  |  |  | 1,059 |
Net write-offs, 2018 |  |  |  |  |  |  | 468 |
Net write-offs, 2017 |  |  |  |  |  |  | 123 |
Nine Months Ended September 30, 2021 Net write-offs |  |  |  |  |  |  | 1,650 |
Rehabilitation loans | Debt-to-Value Ratio, Less than 80 Percent |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 13,717 |  |  |  |  |  | 13,717 |
2020 | 27,910 |  |  |  |  |  | 27,910 |
2019 | 214,618 |  |  |  |  |  | 214,618 |
2018 | 31,228 |  |  |  |  |  | 31,228 |
2017 | 3,427 |  |  |  |  |  | 3,427 |
Prior | 0 |  |  |  |  |  | 0 |
Residential whole loans, total or weighted average | 290,900 |  |  |  |  |  | 290,900 |
Rehabilitation loans | Debt-to-Value Ratio, 81 to 100 Percent |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 0 |  |  |  |  |  | 0 |
2020 | 0 |  |  |  |  |  | 0 |
2019 | 1,226 |  |  |  |  |  | 1,226 |
2018 | 796 |  |  |  |  |  | 796 |
2017 | 1,700 |  |  |  |  |  | 1,700 |
Prior | 0 |  |  |  |  |  | 0 |
Residential whole loans, total or weighted average | 3,722 |  |  |  |  |  | 3,722 |
Single-family rental loans |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 15,502 |  |  |  |  |  | 15,502 |
2020 | 37,602 |  |  |  |  |  | 37,602 |
2019 | 213,416 |  |  |  |  |  | 213,416 |
2018 | 91,870 |  |  |  |  |  | 91,870 |
2017 | 10,537 |  |  |  |  |  | 10,537 |
Prior | 0 |  |  |  |  |  | 0 |
Residential whole loans, total or weighted average | 368,927 |  |  |  |  |  | 368,927 |
Gross write-offs, 2019 |  |  |  |  |  |  | 56 |
Nine Months Ended September 30, 2021 Gross write-offs |  |  |  |  |  |  | 56 |
Net write-offs, 2019 |  |  |  |  |  |  | 56 |
Nine Months Ended September 30, 2021 Net write-offs |  |  |  |  |  |  | 56 |
Single-family rental loans | Debt-to-Value Ratio, Less than 80 Percent |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 15,502 |  |  |  |  |  | 15,502 |
2020 | 37,089 |  |  |  |  |  | 37,089 |
2019 | 208,010 |  |  |  |  |  | 208,010 |
2018 | 91,783 |  |  |  |  |  | 91,783 |
2017 | 10,537 |  |  |  |  |  | 10,537 |
Prior | 0 |  |  |  |  |  | 0 |
Residential whole loans, total or weighted average | 362,921 |  |  |  |  |  | 362,921 |
Single-family rental loans | Debt-to-Value Ratio, 81 to 100 Percent |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 0 |  |  |  |  |  | 0 |
2020 | 513 |  |  |  |  |  | 513 |
2019 | 5,406 |  |  |  |  |  | 5,406 |
2018 | 87 |  |  |  |  |  | 87 |
2017 | 0 |  |  |  |  |  | 0 |
Prior | 0 |  |  |  |  |  | 0 |
Residential whole loans, total or weighted average | 6,006 |  |  |  |  |  | 6,006 |
Seasoned performing loans |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 0 |  |  |  |  |  | 0 |
2020 | 0 |  |  |  |  |  | 0 |
2019 | 0 |  |  |  |  |  | 0 |
2018 | 0 |  |  |  |  |  | 0 |
2017 | 0 |  |  |  |  |  | 0 |
Prior | 110,162 |  |  |  |  |  | 110,162 |
Residential whole loans, total or weighted average | 110,162 |  |  |  |  |  | 110,162 |
Seasoned performing loans | Debt-to-Value Ratio, Less than 80 Percent |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 0 |  |  |  |  |  | 0 |
2020 | 0 |  |  |  |  |  | 0 |
2019 | 0 |  |  |  |  |  | 0 |
2018 | 0 |  |  |  |  |  | 0 |
2017 | 0 |  |  |  |  |  | 0 |
Prior | 105,348 |  |  |  |  |  | 105,348 |
Residential whole loans, total or weighted average | 105,348 |  |  |  |  |  | 105,348 |
Seasoned performing loans | Debt-to-Value Ratio, 81 to 100 Percent |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 0 |  |  |  |  |  | 0 |
2020 | 0 |  |  |  |  |  | 0 |
2019 | 0 |  |  |  |  |  | 0 |
2018 | 0 |  |  |  |  |  | 0 |
2017 | 0 |  |  |  |  |  | 0 |
Prior | 4,814 |  |  |  |  |  | 4,814 |
Residential whole loans, total or weighted average | 4,814 |  |  |  |  |  | 4,814 |
Purchased credit deteriorated loans |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 0 |  |  |  |  |  | 0 |
2020 | 0 |  |  |  |  |  | 0 |
2019 | 0 |  |  |  |  |  | 0 |
2018 | 0 |  |  |  |  |  | 0 |
2017 | 621 |  |  |  |  |  | 621 |
Prior | 574,609 |  |  |  |  |  | 574,609 |
Residential whole loans, total or weighted average | 575,230 |  |  |  |  |  | 575,230 | $ 673,708
Gross write-offs, prior |  |  |  |  |  |  | 406 |
Nine Months Ended September 30, 2021 Gross write-offs |  |  |  |  |  |  | 406 |
Net write-offs |  |  |  |  |  |  | 406 |
Nine Months Ended September 30, 2021 Net write-offs |  |  |  |  |  |  | 406 |
Purchased credit deteriorated loans | Debt-to-Value Ratio, Less than 80 Percent |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 0 |  |  |  |  |  | 0 |
2020 | 0 |  |  |  |  |  | 0 |
2019 | 0 |  |  |  |  |  | 0 |
2018 | 0 |  |  |  |  |  | 0 |
2017 | 621 |  |  |  |  |  | 621 |
Prior | 421,264 |  |  |  |  |  | 421,264 |
Residential whole loans, total or weighted average | 421,885 |  |  |  |  |  | 421,885 |
Purchased credit deteriorated loans | Debt-to-Value Ratio, 81 to 100 Percent |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
2021 | 0 |  |  |  |  |  | 0 |
2020 | 0 |  |  |  |  |  | 0 |
2019 | 0 |  |  |  |  |  | 0 |
2018 | 0 |  |  |  |  |  | 0 |
2017 | 0 |  |  |  |  |  | 0 |
Prior | 153,345 |  |  |  |  |  | 153,345 |
Residential whole loans, total or weighted average | 153,345 |  |  |  |  |  | 153,345 |
Settled Whole Loans | Non-QM loans |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
Purchased performing loans | 2,825,883 |  |  |  |  |  | $ 2,825,883 | $ 2,336,117
Ratio Loan-To-Value |  |  |  |  |  |  | 64.00% | 64.00%
Settled Whole Loans | Rehabilitation loans |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
Purchased performing loans | 587,539 |  |  |  |  |  | $ 587,539 | $ 563,430
Ratio Loan-To-Value |  |  |  |  |  |  | 66.00% | 63.00%
Settled Whole Loans | Single-family rental loans |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
Purchased performing loans | 739,428 |  |  |  |  |  | $ 739,428 | $ 442,456
Ratio Loan-To-Value |  |  |  |  |  |  | 70.00% | 70.00%
Settled Whole Loans | Seasoned performing loans |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
Purchased performing loans | 110,112 |  |  |  |  |  | $ 110,112 | $ 136,157
Ratio Loan-To-Value |  |  |  |  |  |  | 38.00% | 40.00%
Settled Whole Loans | Certain rehabilitation loans |  |  |  |  |  |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |  |  |  |  |  |
Purchased performing loans | $ 142,700 |  |  |  |  |  | $ 142,700 | $ 189,900
Ratio Loan-To-Value |  |  | 69.00% |  |  |  | 70.00% |

X
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- Definition Financing Receivable, Originated Four Years before Latest Fiscal Year, Gross Write-Offs + References No definition available. + Details
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- Definition Financing Receivable, Originated Four Years Before Latest Fiscal Year, Net Write-Offs + References No definition available. + Details
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- Definition Financing Receivable, Originated Three Years before Latest Fiscal Year, Gross Write-Offs + References No definition available. + Details
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- Definition Financing Receivable, Originated Three Years before Latest Fiscal Year, Net Write-Offs + References No definition available. + Details
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- Definition Financing Receivable, Originated Two Years before Latest Fiscal Year, Gross Write-Offs + References No definition available. + Details
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- Definition Financing Receivable, Originated Two Years before Latest Fiscal Year, Net Write-Offs + References No definition available. + Details
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- Definition The LTV of which the Company has assessed its residential whole loans at carrying value will have a higher likelihood of default than newly originated mortgage loans + References No definition available. + Details
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- Definition Amount, after recovery, of writeoff of financing receivable, charged against allowance for credit loss. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 55 -Paragraph 79 -URI http://asc.fasb.org/extlink&oid=124267575&loc=SL82922352-210448 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher SEC -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph (a) -Subparagraph (4) + Details
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- Definition Amount of financing receivable originated more than five years prior to current fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 55 -Paragraph 79 -URI http://asc.fasb.org/extlink&oid=124267575&loc=SL82922352-210448 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919232-210447 + Details
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- Definition Amount of financing receivable originated four years prior to current fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 55 -Paragraph 79 -URI http://asc.fasb.org/extlink&oid=124267575&loc=SL82922352-210448 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919232-210447 + Details
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- Definition Amount of financing receivable originated in current fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 55 -Paragraph 79 -URI http://asc.fasb.org/extlink&oid=124267575&loc=SL82922352-210448 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919232-210447 + Details
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