Real Estate Intangibles (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Real Estate Intangible Amortization [Abstract]
Rental income related to above/below market tenant leases, net	$ (972)	$ 1,118	$ 452	$ 2,439
Property operating expenses related to above/below market ground leases, net	(555)	(315)	(1,219)	(851)
Depreciation and amortization related to in place lease intangibles and lease commissions	$ (22,271)	$ (28,263)	$ (78,114)	$ (69,804)