Real Estate Intangibles (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Real Estate Intangible Amortization [Abstract]
Rental income related to above/below market tenant leases, net	$ 552	$ 926
Property operating expenses related to above/below market ground leases, net	(300)	(268)
Depreciation and amortization related to in place lease intangibles and lease commissions	$ (27,605)	$ (14,610)