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Subsequent Events (Details) - USD ($) |  |  | 2 Months Ended | 3 Months Ended |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Jun. 15, 2020 | Apr. 27, 2020 | May 31, 2020 | Mar. 31, 2020 | Mar. 31, 2019 | Jun. 26, 2020 | Jun. 19, 2020 | Apr. 24, 2020 | Apr. 10, 2020 | Mar. 24, 2020 | Dec. 31, 2019
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from sale of debt securities available-for-sale |  |  |  |  | $ 1,009,316,000 | $ 208,306,000 |  |  |  |  |  |
Residential whole loans, carrying value | [1],[2] |  |  |  | 5,934,042,000 |  |  |  |  |  |  | $ 6,069,370,000
MSR-related assets |  |  |  |  | 738,054,000 |  |  |  |  |  |  | 1,217,002,000
Available-for-sale securities |  |  |  |  | 1,927,454,000 |  |  |  |  |  |  | 3,983,519,000
Repurchase agreements |  |  |  |  | 7,768,180,000 |  |  |  |  |  |  | 9,139,821,000
Cash and cash equivalents |  |  |  |  | 116,465,000 |  |  |  |  |  |  | 70,629,000
Cash on deposit with repurchase agreement counterparties |  |  |  |  | 216,902,000 |  |  |  |  |  |  | 64,035,000
Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Secured debt |  |  |  |  |  |  |  | $ 29,100,000 |  |  |  |
Proceeds from sale of residential mortgage assets |  |  |  | $ 3,200,000,000 |  |  |  |  |  |  |  |
Secured debt decrease |  |  |  | 3,900,000,000 |  |  |  |  |  |  |  |
Proceeds from sale of debt securities available-for-sale |  |  |  | 2,400,000,000 |  |  |  |  |  |  |  |
Proceeds from sale of term notes back by MSR-related collateral |  |  |  | 574,900,000 |  |  |  |  |  |  |  |
Proceeds from sale of other interest earning assets |  |  |  | 15,600,000 |  |  |  |  |  |  |  |
Available-for-salesecurities, realized gains |  |  |  | 177,500,000 |  |  |  |  |  |  |  |
Unrealized gain on securities |  |  |  | 57,000,000.0 |  |  |  |  |  |  |  |
Proceeds from sale of residential whole loans |  |  |  | 845,200,000 |  |  |  |  |  |  |  |
Available-for-sale securities, gross realized losses |  |  |  | 128,400,000 |  |  |  |  |  |  |  |
Realized loss, net of reversal |  |  |  | 58,200,000 |  |  |  |  |  |  |  |
Residential whole loans, net |  |  |  | 6,600,000,000 |  |  |  |  |  |  |  |
Residential whole loans, carrying value |  |  |  | 6,200,000,000 |  |  |  |  |  |  |  |
MSR-related assets |  |  |  | 235,400,000 |  |  |  |  |  |  |  |
Available-for-sale securities |  |  |  | 136,400,000 |  |  |  |  |  |  |  |
Repurchase agreements |  |  |  | $ 3,800,000,000 |  |  |  |  |  |  |  |
Debt to equity ratio |  |  |  | 190.00% |  |  |  |  |  |  |  |
Cash and cash equivalents |  |  |  |  |  |  |  | 343,600,000 |  |  |  |
Cash on deposit with repurchase agreement counterparties |  |  |  |  |  |  |  | $ 103,500,000 |  |  |  |
Repurchase Agreement Financing Arrangements |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Secured debt |  |  |  |  |  |  |  |  |  |  | $ 9,500,000,000 |
Initial FBA | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Secured debt |  |  |  |  |  |  |  |  |  | $ 5,800,000,000 |  |
Second FBA | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Secured debt |  |  |  |  |  |  |  |  | $ 5,300,000,000 |  |  |
Cash payment to counterparties |  |  | $ 150,000,000 |  |  |  |  |  |  |  |  |
Investment Agreement | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Warrant, number of securities callable by each warrant (in shares) |  |  |  |  |  |  | 37,039,106 |  |  |  |  |
Participating Counterparties | Initial FBA | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Secured debt |  |  |  |  |  |  |  |  |  | $ 4,800,000,000 |  |
Secured debt as a percent |  |  |  |  |  |  |  |  |  | 83.00% |  |
Collateralized financings |  |  |  |  |  |  |  |  |  | $ 1,300,000,000 |  |
Participating Counterparties | Second FBA | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Secured debt |  |  | $ 4,400,000,000 |  |  |  |  |  |  |  |  |
Secured debt as a percent |  |  | 84.00% |  |  |  |  |  |  |  |  |
Term Loan Facility | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Maximum borrowing capacity |  | $ 500,000,000 |  |  |  |  |  |  |  |  |  |
Original issue discount, term loan |  | 1.00% |  |  |  |  |  |  |  |  |  |
Stated interest rate |  | 11.00% |  |  |  |  |  |  |  |  |  |
Optional prepayment rate prior to 3rd anniversary |  | 3.00% |  |  |  |  |  |  |  |  |  |
Interest rate increase on third anniversary |  | 1.00% |  |  |  |  |  |  |  |  |  |
Additional interest rate increase on each subsequent anniversary of the Funding Date |  | 1.00% |  |  |  |  |  |  |  |  |  |
Increase upon of default status |  | 2.00% |  |  |  |  |  |  |  |  |  |
Optional Prepayment Amount |  | $ 250,000,000 |  |  |  |  |  |  |  |  |  |
Asset Level Debt Facility | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Maximum borrowing capacity |  |  |  |  |  |  | $ 1,650,000,000 |  |  |  |  |
Amount of shares agreed to be purchased by counterparty |  |  |  |  |  |  | 4.90% |  |  |  |  |
Aggregate gross purchase price per Agreement |  |  |  |  |  |  | $ 50,000,000 |  |  |  |  |
Agency MBS |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Available-for-sale securities |  |  |  |  | 553,413,000 |  |  |  |  |  |  | 1,664,582,000
Repurchase agreements |  |  |  |  | 522,209,000 |  |  |  |  |  |  | 1,557,675,000
Agency MBS | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from sale of debt securities available-for-sale |  |  |  | $ 533,100,000 |  |  |  |  |  |  |  |
Non-Agency MBS |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Available-for-sale securities |  |  |  |  | 1,119,940,000 |  |  |  |  |  |  | 2,063,529,000
Repurchase agreements |  |  |  |  | 1,003,122,000 |  |  |  |  |  |  | 1,121,802,000
Non-Agency MBS | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from sale of debt securities available-for-sale |  |  |  | 1,100,000,000 |  |  |  |  |  |  |  |
CRT securities |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Available-for-sale securities |  |  |  |  | 254,101,000 |  |  |  |  |  |  | 255,408,000
Repurchase agreements |  |  |  |  | $ 297,628,000 |  |  |  |  |  |  | $ 203,569,000
CRT securities | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from sale of debt securities available-for-sale |  |  |  | $ 207,400,000 |  |  |  |  |  |  |  |
First Three Years | Term Loan Facility | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate |  | 3.75% |  |  |  |  |  |  |  |  |  |
After Third Year | Term Loan Facility | Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate |  | 4.50% |  |  |  |  |  |  |  |  |  |
[1] | Includes Non-QM loans held-for-sale with an amortized cost of $965.5 million and a net carrying value of $895.3 million at March 31, 2020.
[2] | Includes approximately $185.9 million and $186.4 million of Residential whole loans, at carrying value and $516.4 million and $567.4 million of Residential whole loans, at fair value transferred to consolidated variable interest entities (“VIEs”) at March 31, 2020 and December 31, 2019, respectively. Such assets can be used only to settle the obligations of each respective VIE

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