Investments in Unconsolidated Real Estate Joint Ventures (Joint Venture Fees) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Management, Leasing and Marketing Fees [Line Items]
Fees received	$ 1,121	$ 1,283
Development and Leasing Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees received	192	581
Loan Guarantee Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees received	182	196
Management and Marketing Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees received	$ 747	$ 506