Related Party Transactions: Summary of Fees (Details) (Vornado [member], USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Summary of fees to Vornado [Line Items]
Fees to Related Party	$ 3,218	$ 3,710	$ 6,046	$ 7,289
Company management fees
Summary of fees to Vornado [Line Items]
Fees to Related Party	750	750	1,500	1,500
Development fees
Summary of fees to Vornado [Line Items]
Fees to Related Party	187	188	375	376
Leasing Fees
Summary of fees to Vornado [Line Items]
Fees to Related Party	1,006	1,765	1,629	3,280
Property Management Fees
Summary of fees to Vornado [Line Items]
Fees to Related Party	$ 1,275	$ 1,007	$ 2,542	$ 2,133