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Loans and Investments - Loan Modifications (Details) $ in Thousands | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2023 USD ($) | Jun. 30, 2021 USD ($) | Dec. 31, 2023 USD ($) loan | Jun. 30, 2023 USD ($) | Dec. 31, 2023 USD ($) loan | Dec. 31, 2022 USD ($) loan | Dec. 31, 2021 USD ($) loan | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($)
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Recoveries of reserves |  |  |  |  | $ 4,776 | $ 1,500 | $ 24,315 |  |
Loans and investments, gross |  |  | $ 12,615,006 |  | 12,615,006 | 14,456,123 |  |  |
Interest reserve |  |  |  |  | 156,100 | 123,700 |  |  |
Principal paydowns |  |  |  |  | 3,354,055 | 3,818,554 | 2,516,771 |  |
Purchase of loan |  |  |  |  | 1,362,171 | 5,955,061 | 9,209,475 |  |
Loans and investments, net allowance for credit losses |  |  | 195,664 |  | $ 195,664 | $ 132,559 | $ 113,241 | $ 148,329 |
Proceeds from full satisfaction of loans |  | $ 95,000 |  |  |  |  |  |  |
Reversal of allowance for credit losses |  | 7,500 |  |  |  |  |  |  |
Interest income from loans |  | $ 3,500 |  |  |  |  |  |  |
Loan modification, refinancing, and extensions | loan |  |  |  |  | 0 | 0 | 0 |  |
Bridge Loans |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) |  |  |  | 3.40% |  |  |  |  |
Loans and investments, gross |  |  | 12,273,244 | $ 70,500 | $ 12,273,244 | $ 14,096,054 |  |  |
Financing receivable, fixed interest rate | 0.0300 |  |  |  |  |  |  |  |
Financing receivable, accrual rate | 0.0300 |  |  |  |  |  |  |  |
Financing receivable, total fixed rate | 0.0600 |  |  |  |  |  |  |  |
Financing receivable, borrower required funding | $ 10,500 |  |  |  |  |  |  |  |
Interest reserve | 2,500 |  |  |  |  |  |  |  |
Financing receivable, borrower requirement, capital improvements | $ 8,000 |  |  |  |  |  |  |  |
Mezzanine Loans |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Loans and investments, gross |  |  | 248,457 |  | 248,457 | 213,499 |  |  |
Multifamily |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Loans and investments, net allowance for credit losses |  |  | $ 110,847 |  | 110,847 | 37,961 | $ 18,707 | 36,468 |
Multifamily | Bridge Loans | Interest Deferral, Extended Maturity, And Interest Forgiveness |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Number of financing receivables modified during period | loan |  |  | 3 |  |  |  |  |  |
Financing receivable, amount modified in period |  |  | $ 241,000 |  |  |  |  |  |
Financing receivable modified, weighted average term increase from modification |  |  | 1 year |  |  |  |  |  |
Percentage of deferred interest waived |  |  | 0.25 |  |  |  |  |  |
Multifamily | Bridge Loans | Interest Deferral, Extended Maturity, And Interest Forgiveness | Minimum |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Percentage of interest foregone |  |  | 0.0200 |  |  |  |  |  |
Multifamily | Bridge Loans | Interest Deferral, Extended Maturity, And Interest Forgiveness | Minimum | Secured Overnight Financing Rate (SOFR) |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) |  |  | 4.00% |  |  |  |  |  |
Multifamily | Bridge Loans | Interest Deferral, Extended Maturity, And Interest Forgiveness | Maximum |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Percentage of interest foregone |  |  | 0.0215 |  |  |  |  |  |
Multifamily | Bridge Loans | Interest Deferral, Extended Maturity, And Interest Forgiveness | Maximum | Secured Overnight Financing Rate (SOFR) |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) |  |  | 4.30% |  |  |  |  |  |
Multifamily | Bridge Loans | Rate of Interest and Extended Maturity |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Financing receivable, amount modified in period |  |  | $ 86,900 |  |  |  |  |  |
Financing receivable modified, weighted average term increase from modification |  |  | 1 year |  |  |  |  |  |
Financing receivable modified, pay rate of interest |  |  | $ 500 |  |  |  |  |  |
Multifamily | Bridge Loans | Rate of Interest and Extended Maturity | Secured Overnight Financing Rate (SOFR) |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) |  |  | 4.25% |  |  |  |  |  |
Office |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Financing receivable, net of reserve |  |  | $ 37,100 |  | 37,100 |  |  |  |
Loan reserve |  |  | 8,000 |  | 8,000 |  |  |  |
Recoveries of reserves |  |  | 2,300 |  |  |  |  |  |
Loans and investments, net allowance for credit losses |  |  | 142 |  | 142 | 8,162 | 8,073 | 1,846 |
Retail |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Recoveries of reserves |  |  |  |  | 2,500 |  |  |  |
Loans and investments, net allowance for credit losses |  |  | $ 3,293 |  | $ 3,293 | $ 5,819 | 5,819 | $ 13,861 |
Retail | Loan Modification Agreement |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Percentage of interest foregone |  |  |  |  |  |  |  | 2.00 |
Maturity period (in years) |  |  |  |  |  |  |  | 3 years |
Principal paydowns |  |  |  |  |  |  |  | $ 6,000 |
Principal reduction |  |  |  |  |  |  |  | 8,000 |
Additional reserve deposit |  |  |  |  |  |  |  | $ 4,600 |
Retail | LIBOR | Loan Modification Agreement |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) |  |  |  |  |  |  |  | 5.50% |
LIBOR floor rate |  |  |  |  |  |  |  | 6.50% |
Retail | Bridge Loans | Loan Modification Agreement |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Principal amount |  |  |  |  |  |  |  | $ 26,500 |
Retail | Bridge Loans | LIBOR | Loan Modification Agreement |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) |  |  |  |  |  |  |  | 6.00% |
LIBOR floor rate |  |  |  |  |  |  |  | 2.375% |
Retail | Mezzanine Loans | Loan Modification Agreement |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Principal amount |  |  |  |  |  |  |  | $ 6,100 |
Fixed rate of interest (as a percent) |  |  |  |  |  |  |  | 12.00% |
Hotel | Forbearance Agreement |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Fixed rate of interest (as a percent) |  | 9.50% |  |  |  |  |  |  |
Principal reduction |  |  |  |  |  |  |  | $ 10,000 |
Pay rate (as a percent) |  |  |  |  |  |  |  | 1.00% |
Hotel | LIBOR | Forbearance Agreement |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Variable rate, spread (as a percent) |  |  |  |  |  |  |  | 3.00% |
LIBOR floor rate |  |  |  |  |  |  |  | 1.50% |
Hotel | Bridge Loans |  |  |  |  |  |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |  |  |  |  |  |
Principal amount |  |  |  |  |  |  |  |  | $ 110,000
Purchase of loan |  |  |  |  |  |  | 60,000 |  | $ 50,000
Loans and investments, net allowance for credit losses |  |  |  |  |  |  | 7,500 |  |
Loan discount |  |  |  |  |  |  | $ 39,900 |  |
Total discount received |  |  |  |  |  |  |  | $ 20,100 |

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- Definition Amount of increase (decrease) in 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. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 948 -SubTopic 310 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-29(Footnote 6)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479851/948-310-S99-1 + Details
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