Investments in Unconsolidated Real Estate Joint Ventures (Joint Venture Fees) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Management, Leasing and other services [Line Items]
Fees received	$ 1,342	$ 1,199
Management and Marketing Fee [Member]
Management, Leasing and other services [Line Items]
Fees received	566	567
Leasing and other fees [Member]
Management, Leasing and other services [Line Items]
Fees received	31	46
Expense reimbursements from unconsolidated joint ventures [Member]
Management, Leasing and other services [Line Items]
Fees received	$ 745	$ 586