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Property Acquisitions (Details) $ in Millions | Sep. 30, 2021 USD ($) ft² | Jun. 30, 2021 USD ($) ft² | Jan. 31, 2021 USD ($) ft²
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Property Acquisitions |  |  |
Area of Real Estate Property | 28,035,572 |  |
885 Third Avenue |  |  |
Property Acquisitions |  |  |
Area of Real Estate Property |  |  | 625,000
Gross Asset Valuation (in millions) | $ |  |  | $ 387.9
461 Fifth Avenue |  |  |
Property Acquisitions |  |  |
Area of Real Estate Property |  | 200,000 |
Gross Asset Valuation (in millions) | $ |  | $ 28.0 |
1591-1597 Broadway (3) |  |  |
Property Acquisitions |  |  |
Area of Real Estate Property | 7,684 |  |
Gross Asset Valuation (in millions) | $ | $ 121.0 |  |
690 Madison Avenue |  |  |
Property Acquisitions |  |  |
Area of Real Estate Property | 7,848 |  |
Gross Asset Valuation (in millions) | $ | $ 72.2 |  |

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