Investments in Unconsolidated Real Estate Joint Ventures (Joint Venture Fees) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Management, Leasing and other services [Line Items]
Fees received	$ 583	$ 588	$ 1,826	$ 1,776
Management and Marketing Fee [Member]
Management, Leasing and other services [Line Items]
Fees received	571	564	1,704	1,676
Leasing and other fees [Member]
Management, Leasing and other services [Line Items]
Fees received	$ 12	$ 24	$ 122	$ 100