Investments in Partially Owned Entities (Schedule of Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Carrying amount of investments in partially owned entities	$ 2,691,478	$ 2,610,558
Other Liabilities
Schedule of Equity Method Investments [Line Items]
Carrying amount of investments in partially owned entities	$ (89,530)	(81,229)
Fifth Avenue and Times Square JV
Schedule of Equity Method Investments [Line Items]
Interest	51.50%
Carrying amount of investments in partially owned entities	$ 2,235,546	2,242,972
Partially owned office buildings/land
Schedule of Equity Method Investments [Line Items]
Carrying amount of investments in partially owned entities	$ 186,190	118,558
Alexander's
Schedule of Equity Method Investments [Line Items]
Interest	32.40%
Carrying amount of investments in partially owned entities	$ 68,492	87,510
Other equity method investments
Schedule of Equity Method Investments [Line Items]
Carrying amount of investments in partially owned entities	$ 201,250	161,518
7 West 34th Street
Schedule of Equity Method Investments [Line Items]
Interest	53.00%
7 West 34th Street | Other Liabilities
Schedule of Equity Method Investments [Line Items]
Carrying amount of investments in partially owned entities	$ (70,552)	(69,899)
85 Tenth Avenue
Schedule of Equity Method Investments [Line Items]
Interest	49.90%
85 Tenth Avenue | Other Liabilities
Schedule of Equity Method Investments [Line Items]
Carrying amount of investments in partially owned entities	$ (18,978)	$ (11,330)