Relationship with Vornado: Summary of Fees (Details) (Affiliated Entity [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Related Party Transaction [Line Items]
Fees to Related Party (in US Dollars)	$ 1,904	$ 2,502	$ 5,756	$ 8,548
Company Management Fees [Member]
Related Party Transaction [Line Items]
Fees to Related Party (in US Dollars)	700	750	2,100	2,250
Development fees [Member]
Related Party Transaction [Line Items]
Fees to Related Party (in US Dollars)	0	63	0	438
Leasing Fees [Member]
Related Party Transaction [Line Items]
Fees to Related Party (in US Dollars)	225	320	903	1,949
Property Management Fees [Member]
Related Party Transaction [Line Items]
Fees to Related Party (in US Dollars)	$ 979	$ 1,369	$ 2,753	$ 3,911