Real Estate Intangibles (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Real Estate Intangible Amortization [Abstract]
Rental income related to above/below market tenant leases, net	$ 213	$ 282	$ 361	$ 887
Property operating expenses related to above/below market ground leases, net	(303)	(347)	(606)	(647)
Depreciation and amortization related to in place lease intangibles and lease commissions	$ (39,083)	$ (28,551)	$ (89,659)	$ (55,843)