Related Party Transactions (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Managment and Development Agreement [line items]
Property Management Fee agreement	Management and Development Agreements We pay Vornado an annual management fee equal to the sum of (i) $3,000,000, (ii) 3% of gross income from the Kings Plaza Regional Shopping Center, (iii) 2% of gross income from the Rego Park II Shopping Center, (iv) $0.50 per square foot of the tenant-occupied office and retail space at 731 Lexington Avenue, and (v) $256,000, escalating at 3% per annum, for managing the common area of 731 Lexington Avenue. In addition, Vornado is entitled to a development fee of 6% of development costs, as defined, with minimum guaranteed fees of $750,000 per annum.
Leasing Agreement [Line Items]
Leasing service fee payable, description	Vornado also provides us with leasing services for a fee of 3% of rent for the first ten years of a lease term, 2% of rent for the eleventh through the twentieth year of a lease term, and 1% of rent for the twenty-first through thirtieth year of a lease term, subject to the payment of rents by tenants. In the event third-party real estate brokers are used, the fees to Vornado increase by 1% and Vornado is responsible for the fees to the third-party real estate brokers.
Debt Instrument, Description of Variable Rate Basis	LIBOR
Commission on assets sale payable, description	Vornado is also entitled to a commission upon the sale of any of our assets equal to 3% of gross proceeds, as defined, for asset sales less than $50,000,000 and 1% of gross proceeds, as defined, for asset sales of $50,000,000 or more. The total of these amounts is payable in annual installments in an amount not to exceed $4,000,000, with interest on the unpaid balance at LIBOR plus 1% (1.78% at December 31, 2011).
Mr. Roth, David Mandelbaum, and Russell B. Wight, Jr.
Related Party Transaction [Line Items]
Ownership Interest in the Company	27.20%
IP & Partners Through Vornado
Related Party Transaction [Line Items]
Ownership Interest in the Company	2.00%
Vornado [member]
Related Party Transaction [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	32.40%
Managment and Development Agreement [line items]
Management Fee Agreement Value	$ 3,000,000
Leasing Agreement [Line Items]
Percentage Commissions On Sale Of Assets Under Fifty Million	3.00%
Percentage Commissions On Sale Of Assets Over Fifty Million	1.00%
Leasing services fee and commission on asset sale, annual installment, maximum.	4,000,000
Basis spread over LIBOR	1.00%
Unpaid Balance Effective Interest	1.78%
Other Agreements [Abstract]
Other Supervisory Fees	6.00%
Summary of fees to Vornado [Line Items]
Total	12,870,000	12,336,000	26,298,000
Vornado [member] | Lexington Avenue Property [Member] | Office And Retail Space [Member]
Managment and Development Agreement [line items]
Property Management Fee Agreement Price Per Square Foot	0.5
Vornado [member] | Lexington Avenue Property [Member] | Common Area [Member]
Managment and Development Agreement [line items]
Property Management Fee Agreement Value	256,000
Property Management Fee Escalation Percentage Per Annum	3.00%
Vornado [member] | Kings Plaza Regional Shopping Center [Member]
Managment and Development Agreement [line items]
Property Management Fee Agreement Percentage Of Income	3.00%
Vornado [member] | Rego Park 2 Property [Member]
Managment and Development Agreement [line items]
Property Management Fee Agreement Percentage Of Income	2.00%
Vornado [member] | Company management fees
Summary of fees to Vornado [Line Items]
Total	3,000,000	3,000,000	3,000,000
Vornado [member] | Development fees
Managment and Development Agreement [line items]
Development fee as percentage of development costs	6.00%
Minimum guaranteed development fee per annum	750,000
Summary of fees to Vornado [Line Items]
Total	750,000	727,000	3,215,000
Vornado [member] | Leasing Fees
Leasing Agreement [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%
Summary of fees to Vornado [Line Items]
Total	4,472,000	4,267,000	15,975,000
Fees owed to Vornado	40,728,000
Vornado [member] | Property Management Fees
Summary of fees to Vornado [Line Items]
Total	4,648,000	4,342,000	4,108,000
Fees owed to Vornado	$ 612,000