Related Party Transactions (Details) - Affiliated Entity $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) partner	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Alexander's
Related Party Transaction
Percentage of affiliated entity owned by company	32.40%
Number of other general partners | partner	2
Percentage of affiliated entity owned by related parties	26.00%
Interstate Properties
Related Party Transaction
Percentage of company owned by related party	7.10%
Related party transaction annual fee percentage	4.00%
Term of management agreement	1 year
Period allowed for termination of automatic renewal of management agreement	60 days
Fee and other income from related parties | $	$ 208	$ 206	$ 204