Investments in Unconsolidated Real Estate Joint Ventures (Joint Venture Fees) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Management, Leasing and Marketing Fees [Line Items]
Fees received	$ 1,727	$ 758	$ 3,010	$ 1,324
Development and Leasing Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees received	727	70	1,307	78
Loan Guarantee Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees received	187	146	383	187
Management and Marketing Fee [Member]
Management, Leasing and Marketing Fees [Line Items]
Fees received	$ 813	$ 542	$ 1,320	$ 1,059