Related Party Transactions (Details) ft² in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2018 USD ($) ft² $ / ft²	Dec. 31, 2017 USD ($)
Leasing Agreements
Receivable arising from the straight-lining of rents	$ 168,789	$ 174,713
Rego Park II \| Retail space \| Toys R Us/ Babies R Us
Leasing Agreements
Area of property (in square feet) \| ft²	47
Annual revenue attributable to tenant	$ 2,600
Receivable arising from the straight-lining of rents	$ 500
Vornado
Related Party Transaction
Noncontrolling interest, ownership percentage by parent	32.40%
Management and Development Agreements
Management fee agreement value	$ 2,800
Vornado \| Toys R Us/ Babies R Us
Related Party Transaction
Noncontrolling interest, ownership percentage by parent	32.50%
Vornado \| Property Management Fees \| Rego Park II
Management and Development Agreements
Property management fee, percent fee	2.00%
Vornado \| Property Management Fees \| 731 Lexington Avenue
Management and Development Agreements
Property management fee agreement price per square foot \| $ / ft²	0.50
Vornado \| Property Management Fees \| 731 Lexington Avenue \| Common Area
Management and Development Agreements
Property management fee agreement value	$ 315
Property management fee escalation percentage per annum	3.00%
Vornado \| Development fees
Management and Development Agreements
Development fee as a percentage of development costs	6.00%
Leasing Agreements
Amounts due	$ 146	21
Vornado \| Leasing fees
Leasing Agreements
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 commissions on sale of assets under fifty million	3.00%
Asset sale commission threshold	$ 50,000
Percentage commissions on sale of assets over fifty million	1.00%
Amounts due	$ 13	1,811
Vornado \| Management, property management, cleaning and security fees
Leasing Agreements
Amounts due	$ 549	$ 658
Mr. Roth, Interstate, David Mandelbaum, and Russell B. Wight, Jr.
Related Party Transaction
Noncontrolling interest, ownership percentage by parent	26.20%
IP & Partners Through Vornado
Related Party Transaction
Noncontrolling interest, ownership percentage by parent	2.30%
Tenant Improvements \| Toys R Us/ Babies R Us
Leasing Agreements
Depreciation and amortization	$ 588
Deferred Leasing Costs \| Toys R Us/ Babies R Us
Leasing Agreements
Depreciation and amortization	$ 215

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Asset sale commission threshold.

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

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

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

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

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

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Property Development Fee Escalation Percentage Per Annum

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Amount per square foot paid to related party as property management fees.

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Annual amount paid to related party as property management fees.

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

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Area of a real estate property.

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The cumulative difference between the rental payments required by a lease agreement and the rental income or expense recognized on a straight-line basis, or other systematic and rational basis more representative of the time pattern in which use or benefit is granted or derived from the leased property, expected to be recognized in income or expense over the term of the leased property, by the lessor or lessee, respectively. Such receivable is reduced by allowances attributable to, for instance, credit risk associated with a lessee.

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The aggregate net amount of depreciation, amortization, and accretion recognized during an accounting period. As a noncash item, the net amount is added back to net income when calculating cash provided by or used in operations using the indirect method.

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

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The percentage charged for managing real estate properties.

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Receivables to be collected from (obligations owed to) related parties, net as of the balance sheet date where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth.

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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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