Residential Whole Loans and Bridge Loans - Aging of Delinquent Loans (Details) $ in Thousands	12 Months Ended
Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 USD ($)
Variable Interest Entity [Line Items]
Principal Amount of Loans Subject to Delinquent Principal or Interest	$ 107,019
Residential Whole-Loans
Variable Interest Entity [Line Items]
No of Loans \| loan	2,361
Principal balance	$ 989,143
Loans at fair value	1,023,502	$ 1,008,782
Payments of loan costs	$ 1,018,876	$ 1,007,004
Bridge Loan
Variable Interest Entity [Line Items]
No of Loans \| loan	9
Principal balance	$ 5,834
Loans at fair value	$ 5,428
Current \| Residential Whole-Loans
Variable Interest Entity [Line Items]
No of Loans \| loan	2,329
Principal balance	$ 971,790
Loans at fair value	$ 1,006,271
Current \| Bridge Loan
Variable Interest Entity [Line Items]
No of Loans \| loan	0
Principal balance	$ 0
Loans at fair value	$ 0
1-30 days \| Residential Whole-Loans
Variable Interest Entity [Line Items]
No of Loans \| loan	9
Principal balance	$ 3,146
Loans at fair value	$ 3,285
1-30 days \| Bridge Loan
Variable Interest Entity [Line Items]
No of Loans \| loan	1
Principal balance	$ 75
Loans at fair value	$ 76
31-60 days \| Residential Whole-Loans
Variable Interest Entity [Line Items]
No of Loans \| loan	0
Principal balance	$ 0
Loans at fair value	$ 0
31-60 days \| Bridge Loan
Variable Interest Entity [Line Items]
No of Loans \| loan	0
Principal balance	$ 0
Loans at fair value	$ 0
61-90 days \| Residential Whole-Loans
Variable Interest Entity [Line Items]
No of Loans \| loan	3
Principal balance	$ 1,993
Loans at fair value	$ 1,989
61-90 days \| Bridge Loan
Variable Interest Entity [Line Items]
No of Loans \| loan	2
Principal balance	$ 954
Loans at fair value	$ 935
90+ days \| Residential Whole-Loans
Variable Interest Entity [Line Items]
No of Loans \| loan	20
Principal balance	$ 12,214
Loans at fair value	$ 11,957
90+ days \| Bridge Loan
Variable Interest Entity [Line Items]
No of Loans \| loan	6
Principal balance	$ 4,805
Loans at fair value	$ 4,417

Amount of principal due on delinquent mortgage loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

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