Real Estate Intangibles (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Real Estate Intangible Amortization [Abstract]
Rental income related to above/below market tenant leases, net	$ 509,000	$ 748,000	$ 1,120,000
Property operating expenses related to above/below market ground leases, net	(1,248,000)	(1,208,000)	(1,285,000)
Depreciation and amortization related to in place lease intangibles and lease commissions	$ (214,966,000)	$ (246,938,000)	$ (103,044,000)