Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Assets, at fair value
Unrealized appreciation on TBAs and interest rate futures contracts - at fair value	$ 594	$ 2,428
Total assets at fair value	3,214,551	2,496,758
Liabilities, at fair value
Non-recourse securitization obligation, collateralized by residential mortgage loans	444,289
Total liabilities	452,547	728
Non-Agency RMBS
Assets, at fair value
Fair Value	74,655	113,579
Agency whole pool loan securities
Assets, at fair value
Fair Value	848,204	372,055
Total AOMT CMBS
Assets, at fair value
Fair Value	8,982	10,756
Unrealized appreciation on futures contracts
Assets, at fair value
Unrealized appreciation on TBAs and interest rate futures contracts - at fair value	594
Liabilities, at fair value
Unrealized depreciation on TBAs		728
U.S. Treasury Bills
Assets, at fair value
Fair Value	0	249,999
Unrealized appreciation on TBAs
Assets, at fair value
Unrealized appreciation on TBAs and interest rate futures contracts - at fair value		2,428
Liabilities, at fair value
Unrealized depreciation on TBAs	8,258
Residential mortgage loans
Assets, at fair value
Fair Value	1,279,341	1,061,912
Residential mortgage loans in securitization trust
Assets, at fair value
Fair Value	982,579	667,365
Commercial mortgage loans
Assets, at fair value
Fair Value	20,196	18,664
Level 1
Assets, at fair value
Total assets at fair value	594	252,427
Liabilities, at fair value
Non-recourse securitization obligation, collateralized by residential mortgage loans	0
Total liabilities	8,258	728
Level 1 | Non-Agency RMBS
Assets, at fair value
Fair Value	0	0
Level 1 | Agency whole pool loan securities
Assets, at fair value
Fair Value	0	0
Level 1 | Total AOMT CMBS
Assets, at fair value
Fair Value	0	0
Level 1 | Unrealized appreciation on futures contracts
Assets, at fair value
Unrealized appreciation on TBAs and interest rate futures contracts - at fair value	594
Liabilities, at fair value
Unrealized depreciation on TBAs		728
Level 1 | U.S. Treasury Bills
Assets, at fair value
Fair Value		249,999
Level 1 | Unrealized appreciation on TBAs
Assets, at fair value
Unrealized appreciation on TBAs and interest rate futures contracts - at fair value		2,428
Liabilities, at fair value
Unrealized depreciation on TBAs	8,258
Level 1 | Residential mortgage loans
Assets, at fair value
Fair Value	0	0
Level 1 | Residential mortgage loans in securitization trust
Assets, at fair value
Fair Value	0	0
Level 1 | Commercial mortgage loans
Assets, at fair value
Fair Value	0	0
Level 2
Assets, at fair value
Total assets at fair value	3,202,237	2,237,212
Liabilities, at fair value
Non-recourse securitization obligation, collateralized by residential mortgage loans	444,289
Total liabilities	444,289	0
Level 2 | Non-Agency RMBS
Assets, at fair value
Fair Value	74,655	113,579
Level 2 | Agency whole pool loan securities
Assets, at fair value
Fair Value	848,204	372,055
Level 2 | Total AOMT CMBS
Assets, at fair value
Fair Value	8,982	10,756
Level 2 | Unrealized appreciation on futures contracts
Assets, at fair value
Unrealized appreciation on TBAs and interest rate futures contracts - at fair value	0
Liabilities, at fair value
Unrealized depreciation on TBAs		0
Level 2 | U.S. Treasury Bills
Assets, at fair value
Fair Value		0
Level 2 | Unrealized appreciation on TBAs
Assets, at fair value
Unrealized appreciation on TBAs and interest rate futures contracts - at fair value		0
Liabilities, at fair value
Unrealized depreciation on TBAs	0
Level 2 | Residential mortgage loans
Assets, at fair value
Fair Value	1,274,520	1,056,875
Level 2 | Residential mortgage loans in securitization trust
Assets, at fair value
Fair Value	975,680	665,802
Level 2 | Commercial mortgage loans
Assets, at fair value
Fair Value	20,196	18,145
Level 3
Assets, at fair value
Total assets at fair value	11,720	7,119
Liabilities, at fair value
Non-recourse securitization obligation, collateralized by residential mortgage loans	0
Total liabilities	0	0
Level 3 | Non-Agency RMBS
Assets, at fair value
Fair Value	0	0
Level 3 | Agency whole pool loan securities
Assets, at fair value
Fair Value	0	0
Level 3 | Total AOMT CMBS
Assets, at fair value
Fair Value	0	0
Level 3 | Unrealized appreciation on futures contracts
Assets, at fair value
Unrealized appreciation on TBAs and interest rate futures contracts - at fair value	0
Liabilities, at fair value
Unrealized depreciation on TBAs		0
Level 3 | U.S. Treasury Bills
Assets, at fair value
Fair Value		0
Level 3 | Unrealized appreciation on TBAs
Assets, at fair value
Unrealized appreciation on TBAs and interest rate futures contracts - at fair value		0
Liabilities, at fair value
Unrealized depreciation on TBAs	0
Level 3 | Residential mortgage loans
Assets, at fair value
Fair Value	4,821	5,037
Level 3 | Residential mortgage loans in securitization trust
Assets, at fair value
Fair Value	6,899	1,563
Level 3 | Commercial mortgage loans
Assets, at fair value
Fair Value	$ 0	$ 519