Investments in Unconsolidated Real Estate Joint Ventures (Joint Venture Fees) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Management, Leasing and Marketing Fees [Line Items]
Fees received	$ 609	$ 1,332	$ 1,188	$ 2,453
Management and Marketing Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees received	570	797	1,112	1,544
Development and Leasing Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees received	35	353	67	545
Loan Guarantee Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees received	$ 4	$ 182	$ 9	$ 364