Financing Agreements - Financing Agreements (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2026	Dec. 31, 2025	Apr. 17, 2024	Jan. 31, 2024
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 11,184,403	$ 10,986,858
Fair Value / Carrying Value	$ 11,117,578	$ 10,940,014
Weighted Average Cost of Funding (in Percent)	4.44%	4.51%
Wells Fargo
Financing Agreements [Line Items]
Weighted Average Months to Maturity	3 months
Barclays
Financing Agreements [Line Items]
Weighted Average Months to Maturity	2 months 19 days
Secured debt \| Estimated Fair Value
Financing Agreements [Line Items]
Fair Value / Carrying Value		$ 5,800,000
Weighted Average Cost of Funding (in Percent)	(0.40%)	(0.54%)
Financing agreements, amortized cost	$ 5,800,000	$ 5,900,000
Senior notes \| 8.875% Senior Notes due 2029
Financing Agreements [Line Items]
Stated interest rate (as a percent)	8.875%	8.875%		8.875%
Unpaid Principal Balance	$ 115,000	$ 115,000
Fair Value / Carrying Value	$ 112,246	$ 112,041
Weighted Average Cost of Funding (in Percent)	9.83%	9.83%
Weighted Average Term to Maturity (Months)	2 years 10 months 17 days	3 years 1 month 13 days
Senior notes \| 9.00% Senior Notes due 2029
Financing Agreements [Line Items]
Stated interest rate (as a percent)	9.00%	9.00%	9.00%
Unpaid Principal Balance	$ 75,000	$ 75,000
Fair Value / Carrying Value	$ 72,982	$ 72,858
Weighted Average Cost of Funding (in Percent)	9.94%	9.94%
Weighted Average Term to Maturity (Months)	3 years 4 months 13 days	3 years 7 months 13 days
Residential whole loans \| Secured debt
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 6,332,739	$ 6,377,576
Fair Value / Carrying Value	$ 6,271,123	$ 6,336,462
Weighted Average Cost of Funding (in Percent)	5.02%	5.10%
Residential whole loans \| Secured debt \| Held at Fair Value
Financing Agreements [Line Items]
Fair Value / Carrying Value	$ 5,800,000
Other \| Other secured financing
Financing Agreements [Line Items]
Unpaid Principal Balance	23,713	$ 23,908
Fair Value / Carrying Value	$ 23,713	$ 23,908
Weighted Average Cost of Funding (in Percent)	5.99%	6.40%
Weighted Average Term to Maturity (Months)	4 years 3 months 14 days	4 years 6 months 10 days
Unpaid principal balance, with 60-day call provision	$ 20,000
Agreements with mark-to-market collateral provisions
Financing Agreements [Line Items]
Unpaid Principal Balance	4,573,375	$ 4,313,355
Fair Value / Carrying Value	$ 4,572,944	$ 4,312,729
Weighted Average Cost of Funding (in Percent)	4.36%	4.71%
Agreements with mark-to-market collateral provisions \| 0-3 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 3,597,325
Agreements with mark-to-market collateral provisions \| 3-6 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	356,842
Agreements with mark-to-market collateral provisions \| 6-12 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	261,435
Fair Value / Carrying Value	$ 275,600
Extension period	1 year
Agreements with mark-to-market collateral provisions \| 6-12 Months \| Maximum
Financing Agreements [Line Items]
Extension period	30 months
Agreements with mark-to-market collateral provisions \| Greater than 12 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 357,773
Fair Value / Carrying Value	3,500,000
Agreements with mark-to-market collateral provisions \| Estimated Fair Value
Financing Agreements [Line Items]
Financing agreements, amortized cost	82,100	$ 48,200
Agreements with mark-to-market collateral provisions \| Held at Fair Value \| Estimated Fair Value
Financing Agreements [Line Items]
Fair Value / Carrying Value		48,200
Agreements with mark-to-market collateral provisions \| Residential whole loans and REO
Financing Agreements [Line Items]
Unpaid Principal Balance	1,432,645	1,332,593
Fair Value / Carrying Value	$ 1,432,214	$ 1,331,967
Weighted Average Cost of Funding (in Percent)	5.44%	5.72%
Weighted Average Term to Maturity (Months)	9 months 25 days	11 months 12 days
Agreements with mark-to-market collateral provisions \| Securities
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 3,140,730	$ 2,980,762
Fair Value / Carrying Value	$ 3,140,730	$ 2,980,762
Weighted Average Cost of Funding (in Percent)	3.85%	4.18%
Weighted Average Term to Maturity (Months)	14 days	10 days
Agreements with mark-to-market collateral provisions \| Securities \| 0-3 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 3,140,730
Agreements with mark-to-market collateral provisions \| Securities \| 3-6 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	0
Agreements with mark-to-market collateral provisions \| Securities \| 6-12 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	0
Agreements with mark-to-market collateral provisions \| Securities \| Greater than 12 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	0
Agreements with mark-to-market collateral provisions \| Residential whole loans
Financing Agreements [Line Items]
Unpaid Principal Balance	1,432,645
Agreements with mark-to-market collateral provisions \| Residential whole loans \| 0-3 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	456,595
Agreements with mark-to-market collateral provisions \| Residential whole loans \| 3-6 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	356,842
Agreements with mark-to-market collateral provisions \| Residential whole loans \| 6-12 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	261,435
Agreements with mark-to-market collateral provisions \| Residential whole loans \| Greater than 12 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	357,773
Agreements with mark-to-market collateral provisions \| Residential whole loans \| Not Held at Fair Value
Financing Agreements [Line Items]
Fair Value / Carrying Value	82,100
Agreements with non-mark-to-market collateral provisions \| Estimated Fair Value
Financing Agreements [Line Items]
Fair Value / Carrying Value		$ 61,100
Financing agreements, amortized cost	32,400	61,100
Agreements with non-mark-to-market collateral provisions \| Residential whole loans and REO
Financing Agreements [Line Items]
Unpaid Principal Balance	64,576	82,019
Fair Value / Carrying Value	$ 64,570	$ 82,016
Weighted Average Cost of Funding (in Percent)	5.82%	6.44%
Weighted Average Term to Maturity (Months)	11 months 23 days	1 year 2 months 15 days
Agreements with non-mark-to-market collateral provisions \| Residential whole loans
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 64,576
Agreements with non-mark-to-market collateral provisions \| Residential whole loans \| 0-3 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	14,073
Agreements with non-mark-to-market collateral provisions \| Residential whole loans \| 3-6 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	0
Agreements with non-mark-to-market collateral provisions \| Residential whole loans \| 6-12 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	18,135
Agreements with non-mark-to-market collateral provisions \| Residential whole loans \| Greater than 12 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	32,368
Agreements with non-mark-to-market collateral provisions \| Residential whole loans \| Held at Fair Value
Financing Agreements [Line Items]
Fair Value / Carrying Value	$ 32,400
Impact of net Swap carry
Financing Agreements [Line Items]
Weighted Average Cost of Funding (in Percent)	(0.40%)	(0.54%)