Financing Agreements - Pledged Collateral (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	$ 9,856,421	$ 9,710,754
Accrued interest	39,900	36,400
Non-Mark-to-Market \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	1,411,796	1,513,904
Mark-to-Market \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	2,657,267	2,466,787
Securitized \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	5,787,358	5,730,063
Residential whole loans, at carrying value \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	1,476,667	1,544,086
Residential whole loans, at carrying value \| Non-Mark-to-Market \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	38,737	55,056
Residential whole loans, at carrying value \| Mark-to-Market \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	302,540	318,762
Residential whole loans, at carrying value \| Securitized \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	1,135,390	1,170,268
Residential whole loans, at fair value \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	7,626,141	7,400,221
Residential whole loans, at fair value \| Non-Mark-to-Market \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	1,373,059	1,458,848
Residential whole loans, at fair value \| Mark-to-Market \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	1,632,982	1,414,912
Residential whole loans, at fair value \| Securitized \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	4,620,100	4,526,461
Securities, at fair value \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	682,199	689,818
Securities, at fair value \| Non-Mark-to-Market \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	0	0
Securities, at fair value \| Mark-to-Market \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	682,199	689,818
Securities, at fair value \| Securitized \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	0	0
Other assets: REO \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	71,414	76,629
Other assets: REO \| Non-Mark-to-Market \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	0	0
Other assets: REO \| Mark-to-Market \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	39,546	43,295
Other assets: REO \| Securitized \| Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	31,868	33,334
Non-Agency MBS \| Mark-to-Market
Debt Instrument [Line Items]
Fair value of securities pledged as collateral under financing agreements	486,300	465,600
Securities Sold under Agreements to Repurchase	$ 364,500	$ 327,200

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