Investments in Unconsolidated Real Estate Joint Ventures (Joint Venture Fees) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Management, Leasing and other services [Line Items]
Fees received	$ 1,245	$ 1,142	$ 2,587	$ 2,340
Management and Marketing Fee [Member]
Management, Leasing and other services [Line Items]
Fees received	561	565	1,128	1,133
Leasing and other fees [Member]
Management, Leasing and other services [Line Items]
Fees received	9	65	40	110
Expense reimbursements from unconsolidated joint ventures [Member]
Management, Leasing and other services [Line Items]
Fees received	$ 675	$ 512	$ 1,419	$ 1,097