Investments in Unconsolidated Real Estate Joint Ventures (Joint Venture Fees) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Management, Leasing and Marketing Fees [Line Items]
Fees received	$ 1,253	$ 1,225	$ 4,263	$ 2,548
Development and Leasing Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees received	325	624	1,632	702
Loan Guarantee Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees received	182	23	564	209
Management and Marketing Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees received	$ 746	$ 578	$ 2,067	$ 1,637