Investments in Partially Owned Entities (Schedule of Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Schedule Of Equity Method Investments
Equity in net income	$ 16,279	$ 16,666
Distributions of income from partially owned entities	30,438	38,706
Our share of net income (loss)	$ 16,279	16,666
Fifth Avenue and Times Square JV
Schedule Of Equity Method Investments
Interest	51.50%
Equity in net income	$ 9,291	10,199
Distributions of income from partially owned entities	9,328	9,226
Our share of net income (loss)	$ 18,619	19,425
Alexander's
Schedule Of Equity Method Investments
Interest	32.40%
Equity in net income	$ 5,154	3,571
Management, leasing and development fees	1,180	1,173
Our share of net income (loss)	6,334	4,744
Partially owned office buildings/land
Schedule Of Equity Method Investments
Our share of net income (loss)	(10,403)	(8,963)
Other investments
Schedule Of Equity Method Investments
Our share of net income (loss)	$ 1,729	$ 1,460