Relationship with Vornado: Summary of Fees (Details) (Vornado [member], USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Summary of fees to Vornado [Line Items]
Fees to Related Party	$ 2,502	$ 2,607	$ 8,548	$ 9,896
Company management fees
Summary of fees to Vornado [Line Items]
Fees to Related Party	750	750	2,250	2,250
Development fees
Summary of fees to Vornado [Line Items]
Fees to Related Party	63	187	438	563
Leasing Fees
Summary of fees to Vornado [Line Items]
Fees to Related Party	320	539	1,949	3,819
Property Management Fees
Summary of fees to Vornado [Line Items]
Fees to Related Party	$ 1,369	$ 1,131	$ 3,911	$ 3,264