Property Acquisitions - 2021 Acquisitions (Details) $ in Millions	Dec. 31, 2021 ft²	Sep. 30, 2021 USD ($) ft²	Jun. 30, 2021 USD ($) ft²	Jan. 31, 2021 USD ($) ft²
Business Acquisition [Line Items]
Approximate Square Feet	27,716,872
885 Third Avenue
Business Acquisition [Line Items]
Approximate Square Feet				625,000
Gross Asset Valuation (in millions) | $				$ 387.9
461 Fifth Avenue
Business Acquisition [Line Items]
Approximate Square Feet			200,000
Gross Asset Valuation (in millions) | $			$ 28.0
1591-1597 Broadway (Crowne Plaza)
Business Acquisition [Line Items]
Approximate Square Feet		7,684
Gross Asset Valuation (in millions) | $		$ 121.0
690 Madison Avenue
Business Acquisition [Line Items]
Approximate Square Feet		7,848
Gross Asset Valuation (in millions) | $		$ 72.2