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v3.23.1

Organization, Properties, Basis of Presentation, Financial Instruments and Recent Accounting Standards (Details) | 3 Months Ended |
--- | --- | ---
Mar. 31, 2023 ft² property | Mar. 31, 2022 ft² property
Properties |  |
Number of properties | 20 |
Number of owned and consolidated properties | 21 | 24
Rentable square feet | ft² | 6,263,226 | 6,915,609
FSP Investments LLC |  |
Organization |  |
Ownership interest (as a percent) | 100.00% |
FSP Property Management LLC |  |
Organization |  |
Ownership interest (as a percent) | 100.00% |
FSP Holdings LLC |  |
Organization |  |
Ownership interest (as a percent) | 100.00% |
FSP Protective TRS Corp. |  |
Organization |  |
Ownership interest (as a percent) | 100.00% |

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