Investments in Partially Owned Entities (Schedule of Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Schedule Of Equity Method Investments
Equity in net income			$ 64,228	$ 53,938
Distributions of income from partially owned entities			54,618	88,902
Our share of net income (loss)	$ 47,949	$ 37,272	$ 64,228	53,938
Fifth Avenue and Times Square JV
Schedule Of Equity Method Investments
Interest	51.50%		51.50%
Equity in net income	$ 10,427	5,941	$ 19,718	16,140
Distributions of income from partially owned entities	10,258	9,329	19,586	18,555
Our share of net income (loss)	$ 20,685	15,270	$ 39,304	34,695
Default accrual interest amount		5,120		5,120
Alexander's
Schedule Of Equity Method Investments
Interest	32.40%		32.40%
Equity in net income	$ 2,649	3,318	$ 7,803	6,889
Management, leasing and development fees	1,185	1,699	2,365	2,872
Net gain on sale of land	0	16,396	0	16,396
Our share of net income (loss)	3,834	21,413	10,168	26,157
Partially owned office buildings
Schedule Of Equity Method Investments
Our share of net income (loss)	21,297	(254)	10,894	(9,217)
Gain on extinguishment of debt	31,215		31,215
Other investments
Schedule Of Equity Method Investments
Our share of net income (loss)	$ 2,133	$ 843	$ 3,862	$ 2,303