Relationship with Vornado (Details) (Vornado [member], USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Related Party Transaction [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	32.40%		32.40%
Managment and Development Agreement [Abstract]
Management Fee Agreement Value (in US dollars)			$ 2,800,000
Leasing Agreement [Abstract]
Asset Sale Commission Threshold (in US dollars)			50,000,000
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. (in US dollars)			4,000,000
Debt Instrument, Description of Variable Rate Basis			LIBOR
Basis spread over LIBOR			1.00%
Unpaid Balance Effective Interest	1.58%		1.58%
Other Agreements [Abstract]
Other Supervisory Fees			6.00%
Summary of fees to Vornado
Fees to related party (in US dollars)	4,337,000	1,806,000	8,561,000	5,501,000
Lexington Avenue Property [Member] | Office And Retail Space [Member]
Managment and Development Agreement [Abstract]
Property Management Fee Agreement Price Per Square Foot			0.5
Lexington Avenue Property [Member] | Common Area [Member]
Managment and Development Agreement [Abstract]
Property Management Fee Agreement Value (in US dollars)			280,000
Property Management Fee Escalation Percentage Per Annum			3.00%
Rego Park 2 Property [Member]
Managment and Development Agreement [Abstract]
Property Management Fee Agreement Percentage Of Income			2.00%
Company Management Fees [Member]
Summary of fees to Vornado
Fees to related party (in US dollars)	700,000	700,000	2,100,000	2,100,000
Development fees [Member]
Managment and Development Agreement [Abstract]
Development fee as percentage of development costs			6.00%
Summary of fees to Vornado
Fees to related party (in US dollars)	1,714,000	0	2,463,000	0
Fees owed to Vornado (in US dollars)	2,463,000		2,463,000
Leasing Fees [Member]
Leasing Agreement [Abstract]
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
Fees to related party (in US dollars)	911,000	225,000	1,275,000	903,000
Fees owed to Vornado (in US dollars)	41,197,000		41,197,000
Property Management Fees [Member]
Summary of fees to Vornado
Fees to related party (in US dollars)	1,012,000	881,000	2,723,000	2,498,000
Fees owed to Vornado (in US dollars)	$ 519,000		$ 519,000