Related Party Transactions - Excluded Properties and Businesses (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) office_property interest property	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Retail site | Manhattan
Related Party Transaction [Line Items]
Number of properties | office_property	4
Office building
Related Party Transaction [Line Items]
Number of properties | office_property	14
Office building | Manhattan
Related Party Transaction [Line Items]
Number of properties | office_property	9
Malkin group | Mezzanine and senior equity funds
Related Party Transaction [Line Items]
Number of interests owned | interest	1
Malkin group | Residential property manager
Related Party Transaction [Line Items]
Number of properties | interest	5
Number of interests owned | interest	5
Malkin group | Multi-family property | Greenwich, connecticut
Related Party Transaction [Line Items]
Number of properties	9
Malkin group | Retail site | Greenwich, connecticut
Related Party Transaction [Line Items]
Number of properties	5
Malkin group | Retail site | Manhattan
Related Party Transaction [Line Items]
Number of properties	2
Malkin group | Former post office | Greenwich, connecticut
Related Party Transaction [Line Items]
Number of properties	1
Malkin group | Office building | Manhattan
Related Party Transaction [Line Items]
Number of properties	1
Affiliated entities | Third party management and other fees | Supervisory fee revenue
Related Party Transaction [Line Items]
Revenue from related parties | $	$ 1.0	$ 0.9	$ 0.9
Affiliated entities | Third party management and other fees | Property management fee revenue
Related Party Transaction [Line Items]
Revenue from related parties | $	$ 0.2	$ 0.3	$ 0.3