Asset sale commission threshold.

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- Definition

Development Fee Percentage

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- Definition

Lease Commission, Percentage

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- Definition

Percentage of rent payable to related party for leasing services for the eleventh through twentieth years of the lease.

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No definition available.

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- Definition

Percentage of rent payable to related party for leasing services for the first ten years of the lease.

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No definition available.

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- Definition

Percentage of rent payable to related party for leasing services for the twenty-first through thirtieth years of the lease.

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No definition available.

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- Definition

The amount of management fee paid to related party to manage corporate activities.

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No definition available.

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- Definition

Percentage of gross proceeds over $50,000,000 from the sale of any assets, payable to related party.

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No definition available.

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- Definition

Percentage of gross proceeds under $50,000,000 from the sale of any assets, payable to related party.

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No definition available.

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- Definition

Percentage of increase in leasing services payable to related party if a real estate broker is used

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- Definition

Property Management Fee Agreement, Price Per Square Foot

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No definition available.

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Annual increase in the amount paid to related party as property management fees.

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No definition available.

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- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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No definition available.

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- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

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No definition available.

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- Definition

Amount of liabilities classified as other.

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- Definition

The percentage charged for managing real estate properties.

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No definition available.

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- Definition

Amount of transactions with related party during the financial reporting period.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Related Party Transactions - Narrative (Details)	4 Months Ended	8 Months Ended	12 Months Ended
Related Party Transactions - Narrative (Details)	Apr. 30, 2024	Dec. 31, 2024 USD ($)	Dec. 31, 2024 USD ($) $ / ft²	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Related Party Transaction [Line Items]
Related party transaction, amounts of transaction			$ 15,409,000	$ 10,729,000	$ 10,093,000
Development fees
Related Party Transaction [Line Items]
Related party transaction, amounts of transaction			472,000	0	3,000
Leasing fees
Related Party Transaction [Line Items]
Related party transaction, amounts of transaction			6,084,000	1,213,000	$ 1,378,000
Vornado
Related Party Transaction [Line Items]
Management fee agreement value			2,800,000
Amounts due to Vornado		$ 1,159,000	$ 1,159,000	715,000
Vornado \| Development fees
Related Party Transaction [Line Items]
Development fee as a percentage of development costs			6.00%
Amounts due to Vornado		$ 346,000	$ 346,000
Vornado \| Leasing fees
Related Party Transaction [Line Items]
Lease fee percentage of rent one to ten years			3.00%
Lease fee percentage of rent eleven to twenty years			2.00%
Lease fee percentage of rent twenty first to thirty years			1.00%
Percentage increase lease fee if broker used	1.00%
Percentage of third-party lease commission		33.33%
Percentage commissions on sale of assets under fifty million			3.00%
Asset sale commission threshold			$ 50,000,000
Percentage commissions on sale of assets over fifty million			1.00%
Amounts due to Vornado		$ 171,000	$ 171,000	69,000
Vornado \| Management, property management, cleaning, engineering and security fees
Related Party Transaction [Line Items]
Amounts due to Vornado		$ 642,000	$ 642,000	$ 646,000
Vornado \| Retail space \| Rego Park II \| Property management, cleaning, engineering and security fees
Related Party Transaction [Line Items]
Property management fee, percent fee			2.00%
Vornado \| Office and Retail Space \| 731 Lexington Avenue \| Property management, cleaning, engineering and security fees
Related Party Transaction [Line Items]
Property management fee agreement price per square foot \| $ / ft²			0.50
Vornado \| Common Area \| 731 Lexington Avenue \| Property management, cleaning, engineering and security fees
Related Party Transaction [Line Items]
Property management fee escalation percentage per annum			3.00%
Vornado \| Common Area \| 731 Lexington Avenue \| Base management fee
Related Party Transaction [Line Items]
Related party transaction, amounts of transaction			$ 376,000
Alexander's Inc. \| Vornado \| Vornado
Related Party Transaction [Line Items]
Parent ownership		32.40%	32.40%
Alexander's Inc. \| Director \| Mr. Roth, Interstate, David Mandelbaum and Russell B, Wight, Jr.
Related Party Transaction [Line Items]
Ownership percentage by noncontrolling owners		26.00%	26.00%
Alexander's Inc. \| Indirectly through Vornado \| Directors indirect through Vornado
Related Party Transaction [Line Items]
Ownership percentage by noncontrolling owners		2.30%	2.30%