Financing Agreements - Financing Agreements (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2023	Jan. 11, 2024
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 9,010,522	$ 8,683,152
Fair Value / Carrying Value	$ 8,891,042	$ 8,536,745
Weighted Average Cost of Funding (in Percent)	4.63%	4.33%
Wells Fargo
Financing Agreements [Line Items]
Weighted Average Months to Maturity	15 months 21 days
Barclays
Financing Agreements [Line Items]
Weighted Average Months to Maturity	10 months 3 days
Churchill Finance LLC
Financing Agreements [Line Items]
Weighted Average Months to Maturity	14 months 15 days
Senior Notes \| 8.875% Senior Notes Due 2029
Financing Agreements [Line Items]
Stated interest rate (as a percent)	8.875%		8.875%
Agreements with mark-to-market collateral provisions
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 2,730,010	$ 2,361,146
Fair Value / Carrying Value	$ 2,729,196	$ 2,360,254
Weighted Average Cost of Funding (in Percent)	7.00%	7.09%
Agreements with mark-to-market collateral provisions \| 0-3 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 1,149,960
Agreements with mark-to-market collateral provisions \| 3-6 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	59,396
Agreements with mark-to-market collateral provisions \| 6-12 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	379,962
Fair Value / Carrying Value	$ 356,400
Extension period	1 year
Agreements with mark-to-market collateral provisions \| 6-12 Months \| Maximum
Financing Agreements [Line Items]
Extension period	27 months
Agreements with mark-to-market collateral provisions \| Greater than 12 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 1,140,692
Fair Value / Carrying Value	1,100,000
Agreements with mark-to-market collateral provisions \| Estimated Fair Value
Financing Agreements [Line Items]
Financing agreements, amortized cost	290,200	$ 469,400
Agreements with mark-to-market collateral provisions \| Estimated Fair Value \| Held at Fair Value
Financing Agreements [Line Items]
Fair Value / Carrying Value		469,400
Agreements with mark-to-market collateral provisions \| Residential whole loan
Financing Agreements [Line Items]
Unpaid Principal Balance	1,999,166	1,738,543
Fair Value / Carrying Value	$ 1,998,352	$ 1,737,651
Weighted Average Cost of Funding (in Percent)	7.44%	7.50%
Weighted Average Term to Maturity (Months)	12 months 12 days	11 months 24 days
Agreements with mark-to-market collateral provisions \| Residential whole loan \| 0-3 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 419,116
Agreements with mark-to-market collateral provisions \| Residential whole loan \| 3-6 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	59,396
Agreements with mark-to-market collateral provisions \| Residential whole loan \| 6-12 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	379,962
Agreements with mark-to-market collateral provisions \| Residential whole loan \| Greater than 12 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	1,140,692
Agreements with mark-to-market collateral provisions \| Residential whole loan \| Not Held at Fair Value
Financing Agreements [Line Items]
Fair Value / Carrying Value	290,200
Agreements with mark-to-market collateral provisions \| Securities
Financing Agreements [Line Items]
Unpaid Principal Balance	730,844	$ 622,603
Fair Value / Carrying Value	$ 730,844	$ 622,603
Weighted Average Cost of Funding (in Percent)	5.74%	5.81%
Weighted Average Term to Maturity (Months)	6 days	6 days
Agreements with mark-to-market collateral provisions \| Securities \| 0-3 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 730,844
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 Non-mark-to-market Collateral Provisions \| Estimated Fair Value
Financing Agreements [Line Items]
Fair Value / Carrying Value		$ 178,900
Financing agreements, amortized cost	377,300	178,900
Agreements with Non-mark-to-market Collateral Provisions \| Residential whole loan
Financing Agreements [Line Items]
Unpaid Principal Balance	932,031	1,217,671
Fair Value / Carrying Value	$ 931,146	$ 1,216,697
Weighted Average Cost of Funding (in Percent)	7.95%	7.94%
Weighted Average Term to Maturity (Months)	14 months 27 days	20 months 18 days
Agreements with Non-mark-to-market Collateral Provisions \| Residential whole loan \| 0-3 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 53,815
Agreements with Non-mark-to-market Collateral Provisions \| Residential whole loan \| 3-6 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	17,771
Agreements with Non-mark-to-market Collateral Provisions \| Residential whole loan \| 6-12 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	0
Agreements with Non-mark-to-market Collateral Provisions \| Residential whole loan \| Greater than 12 Months
Financing Agreements [Line Items]
Unpaid Principal Balance	860,445
Agreements with Non-mark-to-market Collateral Provisions \| Residential whole loan \| Held at Fair Value
Financing Agreements [Line Items]
Fair Value / Carrying Value	$ 377,300
Securities \| Estimated Fair Value
Financing Agreements [Line Items]
Fair Value / Carrying Value		$ 4,000,000
Weighted Average Cost of Funding (in Percent)	(1.27%)	(1.40%)
Financing agreements, amortized cost	$ 4,500,000	$ 4,100,000
Securities \| Residential whole loan
Financing Agreements [Line Items]
Unpaid Principal Balance	5,158,481	4,894,746
Fair Value / Carrying Value	$ 5,047,613	$ 4,750,805
Weighted Average Cost of Funding (in Percent)	4.80%	4.37%
Securities \| Residential whole loan \| Held at Fair Value
Financing Agreements [Line Items]
Fair Value / Carrying Value	$ 4,400,000
Convertible senior notes \| Unsecured
Financing Agreements [Line Items]
Unpaid Principal Balance	0	$ 209,589
Fair Value / Carrying Value	$ 0	$ 208,989
Weighted Average Cost of Funding (in Percent)	6.64%	6.94%
Weighted Average Term to Maturity (Months)	0 months	5 months 15 days
8.875% Senior Notes Due 2029 \| Unsecured
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 115,000
Fair Value / Carrying Value	$ 110,912
Weighted Average Cost of Funding (in Percent)	9.84%
Weighted Average Term to Maturity (Months)	55 months 18 days
9.00% Senior Notes Due 2029 \| Unsecured
Financing Agreements [Line Items]
Unpaid Principal Balance	$ 75,000
Fair Value / Carrying Value	$ 72,175
Weighted Average Cost of Funding (in Percent)	9.96%
Weighted Average Term to Maturity (Months)	61 months 15 days
Impact of net Swap carry \| Unsecured
Financing Agreements [Line Items]
Weighted Average Cost of Funding (in Percent)	(1.27%)	(1.40%)