Real Estate Intangibles (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Real Estate Intangible Amortization [Abstract]
Rental income related to above/below market tenant leases, net	$ 282	$ 874	$ 887	$ 1,592
Property operating expenses related to above/below market ground leases, net	(364)	(268)	(682)	(536)
Depreciation and amortization related to in place lease intangibles and lease commissions	$ (28,551)	$ (27,048)	$ (55,843)	$ (41,540)