Residential Whole Loans (Residential Whole Loans, at Carrying Value - Additional Information) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average LTV Ratio	80.00%
Settled Whole Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Residential whole loans, at carrying value, total or weighted average	$ 3,416,124	$ 4,108,499
Amortized Cost Basis	3,470,385	4,195,332
Unpaid Principal Balance (“UPB”)	$ 3,528,066	$ 4,249,418
Weighted Average Coupon	5.67%	5.77%
Weighted Average Term to Maturity (Months)	289 months	282 months
Settled Whole Loans \| Non-QM loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased performing loans	$ 1,948,763	$ 2,336,117
Amortized Cost Basis	1,960,855	2,357,185
Unpaid Principal Balance (“UPB”)	$ 1,908,905	$ 2,294,086
Weighted Average Coupon	5.81%	5.84%
Weighted Average Term to Maturity (Months)	347 months	351 months
Weighted Average LTV Ratio	63.00%	64.00%
Weighted Average FICO Scores	712	712
Settled Whole Loans \| Rehabilitation loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased performing loans	$ 352,859	$ 563,430
Amortized Cost Basis	364,463	581,801
Unpaid Principal Balance (“UPB”)	$ 364,463	$ 581,801
Weighted Average Coupon	7.21%	7.29%
Weighted Average Term to Maturity (Months)	5 months	3 months
Weighted Average LTV Ratio	65.00%	63.00%
Weighted Average FICO Scores	723	719
Settled Whole Loans \| Single-family rental loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased performing loans	$ 415,184	$ 442,456
Amortized Cost Basis	417,544	446,374
Unpaid Principal Balance (“UPB”)	$ 413,060	$ 442,208
Weighted Average Coupon	6.29%	6.32%
Weighted Average Term to Maturity (Months)	322 months	324 months
Weighted Average LTV Ratio	69.00%	70.00%
Weighted Average FICO Scores	730	730
Settled Whole Loans \| Seasoned performing loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased performing loans	$ 118,309	$ 136,157
Amortized Cost Basis	118,366	136,264
Unpaid Principal Balance (“UPB”)	$ 129,536	$ 149,004
Weighted Average Coupon	2.96%	3.30%
Weighted Average Term to Maturity (Months)	167 months	171 months
Weighted Average LTV Ratio	39.00%	40.00%
Weighted Average FICO Scores	722	723
Settled Whole Loans \| Purchased credit impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Residential whole loans, at carrying value	$ 581,009	$ 630,339
Amortized Cost Basis	609,157	673,708
Unpaid Principal Balance (“UPB”)	$ 712,102	$ 782,319
Weighted Average Coupon	4.54%	4.46%
Weighted Average Term to Maturity (Months)	284 months	287 months
Weighted Average LTV Ratio	71.00%	76.00%
Settled Whole Loans \| Certain rehabilitation loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased performing loans	$ 134,200	$ 189,900
Weighted Average LTV Ratio	69.00%	69.00%
Settled Whole Loans \| Current \| Non-QM loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	$ 1,725,889	$ 2,099,134
Settled Whole Loans \| Current \| Rehabilitation loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	226,865	390,706
Settled Whole Loans \| Current \| Single-family rental loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	386,091	415,386
Settled Whole Loans \| Current \| Seasoned performing loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	107,762	124,877
Settled Whole Loans \| 30-59 \| Non-QM loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	58,059	73,163
Settled Whole Loans \| 30-59 \| Rehabilitation loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	17,150	29,315
Settled Whole Loans \| 30-59 \| Single-family rental loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	5,858	6,652
Settled Whole Loans \| 30-59 \| Seasoned performing loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	943	2,186
Settled Whole Loans \| 60-89 \| Non-QM loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	36,856	36,501
Settled Whole Loans \| 60-89 \| Rehabilitation loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	11,506	25,433
Settled Whole Loans \| 60-89 \| Single-family rental loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	3,000	3,948
Settled Whole Loans \| 60-89 \| Seasoned performing loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	538	1,170
Settled Whole Loans \| 90 or more \| Non-QM loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	140,051	148,387
Settled Whole Loans \| 90 or more \| Rehabilitation loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	108,942	136,347
Settled Whole Loans \| 90 or more \| Single-family rental loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	22,595	20,388
Settled Whole Loans \| 90 or more \| Seasoned performing loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	9,123	8,031
Settled Whole Loans \| 90 or more \| Purchased credit impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized Cost Basis	$ 105,487	$ 119,621

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The LTV of which the Company has assessed its residential whole loans at carrying value will have a higher likelihood of default than newly originated mortgage loans

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The recorded balance, net of any applicable reductions (for example, unamortized accretable yield and allowance for loan losses). This relates to loans not accounted for debt securities with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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