Investments in Partially Owned Entities (Schedule of Investments) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Schedule Of Equity Method Investments
Carrying amount of investments in partially owned entities	$ 2,641,297	$ 2,665,073
Other liabilities
Schedule Of Equity Method Investments
Carrying amount of investments in partially owned entities	$ (78,929)	(81,528)
Fifth Avenue and Times Square JV
Schedule Of Equity Method Investments
Equity method ownership percentage	51.50%
Carrying amount of investments in partially owned entities	$ 2,256,952	2,272,320
Partially owned office buildings/land
Schedule Of Equity Method Investments
Carrying amount of investments in partially owned entities	$ 173,950	182,180
Alexander's
Schedule Of Equity Method Investments
Equity method ownership percentage	32.40%
Carrying amount of investments in partially owned entities	$ 96,288	87,796
Other investments
Schedule Of Equity Method Investments
Carrying amount of investments in partially owned entities	$ 114,107	122,777
7 West 34th Street
Schedule Of Equity Method Investments
Equity method ownership percentage	53.00%
7 West 34th Street | Other liabilities
Schedule Of Equity Method Investments
Carrying amount of investments in partially owned entities	$ (67,729)	(65,522)
85 Tenth Avenue
Schedule Of Equity Method Investments
Equity method ownership percentage	49.90%
85 Tenth Avenue | Other liabilities
Schedule Of Equity Method Investments
Carrying amount of investments in partially owned entities	$ (11,200)	$ (16,006)