Loans and Investments - Summary of impaired loans (Details) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2023 USD ($) loan	Dec. 31, 2022 USD ($) loan
Loans and Investments
UPB	$ 293,055	$ 157,960
Carrying Value	280,258	147,131
Allowance for Credit Losses	$ 111,087	$ 85,386
Wtd. Avg. First Dollar LTV Ratio	0.01	0.03
Wtd. Avg. Last Dollar LTV Ratio	0.97	0.96
Number of impaired loans (less unearned revenue and other holdbacks and adjustments) by asset class \| loan	13	7
Land
Loans and Investments
UPB	$ 134,215	$ 134,215
Carrying Value	127,868	127,868
Allowance for Credit Losses	$ 77,869	$ 77,869
Wtd. Avg. First Dollar LTV Ratio	0	0
Wtd. Avg. Last Dollar LTV Ratio	0.99	0.99
Multifamily
Loans and Investments
UPB	$ 90,070
Carrying Value	87,995
Allowance for Credit Losses	$ 17,750
Wtd. Avg. First Dollar LTV Ratio	0
Wtd. Avg. Last Dollar LTV Ratio	1
Office
Loans and Investments
UPB	$ 45,025
Carrying Value	45,025
Allowance for Credit Losses	$ 7,951
Wtd. Avg. First Dollar LTV Ratio	0
Wtd. Avg. Last Dollar LTV Ratio	0.99
Retail
Loans and Investments
UPB	$ 22,045	$ 22,045
Carrying Value	17,670	17,563
Allowance for Credit Losses	$ 5,817	$ 5,817
Wtd. Avg. First Dollar LTV Ratio	0.13	0.14
Wtd. Avg. Last Dollar LTV Ratio	0.78	0.79
Commercial
Loans and Investments
UPB	$ 1,700	$ 1,700
Carrying Value	1,700	1,700
Allowance for Credit Losses	$ 1,700	$ 1,700
Wtd. Avg. First Dollar LTV Ratio	0.63	0.63
Wtd. Avg. Last Dollar LTV Ratio	0.63	0.63

Carrying value of impaired financing receivables.

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- Definition

For an impaired loan, the weighted average loan to value ratio that is calculated by comparing the total of the carrying value of the company's loan and all senior lien positions within the capital stack to the fair value of the underlying collateral to determine the point at which the company will absorb a total loss of its position.

+ References

No definition available.

+ Details

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- Definition

+ References

No definition available.

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- Definition

The number of impaired loans (less unearned revenue and other holdbacks and adjustments) by asset class.

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Subsection 29
-Publisher SEC

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479851/948-310-S99-1

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- Definition

Amount, excluding accrued interest, of allowance for credit loss at acquisition date of financing receivable purchased with credit deterioration. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 19
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-19

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

+ Details

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- Definition

Amount at par value of financing receivable purchased with credit deterioration.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 19
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-19

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