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Financing Agreements - Financing Agreements, at Fair Values Narrative (Details) - USD ($) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2021 | Dec. 31, 2020
Financing Agreements [Line Items] |  |
Financial instruments | $ 6,378,782 | $ 4,336,976
Financing Agreement |  |
Financing Agreements [Line Items] |  |
Cash collateral pledged | 10,200 | $ 7,200
Non-mark-to-market financing secured by residential whole loans |  |
Financing Agreements [Line Items] |  |
Financial instruments | $ 559,800 |
Minimum | Non-mark-to-market financing secured by residential whole loans |  |
Financing Agreements [Line Items] |  |
Facility maturity period | 5 months |
Extension term | 16 months |
Maximum | Non-mark-to-market financing secured by residential whole loans |  |
Financing Agreements [Line Items] |  |
Facility maturity period | 45 months |
Extension term | 42 months |

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- Definition Financing Agreements, Fair Value And Carrying Value + References No definition available. + Details
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- Definition [Line Items] for Financing Agreements [Table] + References No definition available. + Details
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- Definition Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition Amount of right to receive cash collateral under master netting arrangements that have not been offset against securities sold under agreement to repurchase. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226016-175313 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226038-175313 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 + Details
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