Investments in Unconsolidated Real Estate Joint Ventures (Joint Venture Fees) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Management, Leasing and other services [Line Items]
Fees received	$ 630	$ 609	$ 1,243	$ 1,188
Management and Marketing Fee [Member]
Management, Leasing and other services [Line Items]
Fees received	565	570	1,133	1,112
Leasing and other fees [Member]
Management, Leasing and other services [Line Items]
Fees received	$ 65	$ 39	$ 110	$ 76