Real Estate Intangibles (Summary of Real Estate Intangible Amortization) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Real Estate Intangible Amortization [Abstract]
Rental income related to (above)/below market tenant leases, net	$ (1,269)	$ 875	$ 919
Property operating expenses related to above/(below) market ground leases, net	(1,339)	(1,231)	(1,241)
Depreciation and amortization related to in place lease intangibles and lease commissions	$ (122,515)	$ (145,132)	$ (132,141)