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Organization and Basis of Presentation - Narrative (Details) | 1 Months Ended | 12 Months Ended
--- | --- | ---
Jan. 31, 2024 USD ($) | Dec. 31, 2023 USD ($) ft² building shares | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($)
Organization |  |  |  |
Number of Buildings | building |  | 50 |  |
Approximate Square Feet | ft² |  | 29,695,841 |  |
Number of shares to be received on redemption of one unit of limited partnership interests (shares) | shares |  | 1 |  |
Mortgages and other loans payable, net |  | $ 1,491,319,000 | $ 3,227,563,000 |
Repayments of mortgages |  | 25,826,000 | 292,364,000 | $ 375,044,000
Due from joint ventures |  |  |  |
Organization |  |  |  |
Mortgages and other loans payable, net |  | $ 14,799,277,000 | 12,348,954,000 |
2 Herald Square | Due from joint ventures | Subsequent Event |  |  |  |
Organization |  |  |  |
Consideration transferred | $ 0 |  |  |
Investment in joint venture, ownership percentage | 95.00% |  |  |
Mortgages and other loans payable, net | $ 182,500,000 |  |  |
Repayments of mortgages | 7,000,000 |  |  |
717 Fifth Avenue | Due from joint ventures | Subsequent Event |  |  |  |
Organization |  |  |  |
Gross Asset Valuation | $ 963,000,000 |  |  |
Managed Office Properties |  |  |  |
Organization |  |  |  |
Approximate Square Feet | ft² |  | 400,000 |  |
Debt and preferred equity investments including investments held by unconsolidated joint ventures |  | $ 346,700,000 |  |
Debt and preferred equity investments and other financing receivables included in other balance sheet items |  | $ 7,900,000 |  |
Office |  |  |  |
Organization |  |  |  |
Number of Buildings | building |  | 1 |  |
Retail building |  |  |  |
Organization |  |  |  |
Number of Buildings | building |  | 1 |  |
SL Green Operating Partnership |  |  |  |
Organization |  |  |  |
Mortgages and other loans payable, net |  | $ 1,491,319,000 | 3,227,563,000 |
Repayments of mortgages |  | $ 25,826,000 | $ 292,364,000 | $ 375,044,000
Service Corporation |  |  |  |
Organization |  |  |  |
Percentage of ownership in SL Green Management LLC owned by operating partnership (percent) |  | 95.00% |  |
SLG Management LLC | SL Green Management |  |  |  |
Organization |  |  |  |
Percentage of ownership in SL Green Management LLC owned by operating partnership (percent) |  | 100.00% |  |
Operating Partnership | SL Green Operating Partnership |  |  |  |
Organization |  |  |  |
Noncontrolling interest in the operating partnership (as a percent) |  | 5.75% | 5.39% |

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