Real Estate Investments Business Acquisitions (Details) $ in Thousands									9 Months Ended
		Sep. 19, 2014 USD ($)	Sep. 10, 2014 USD ($)	Jul. 15, 2014 USD ($)	Jun. 02, 2014 USD ($)	Mar. 07, 2014 USD ($) property	Feb. 14, 2014 USD ($)	Jan. 31, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 01, 2015 USD ($)
Business Acquisition [Line Items]
Payments for Deposits on Real Estate Acquisitions									$ 2,300
Document Period End Date									Sep. 30, 2015
Purchase Price										$ 217,599
Debt Assumed, Net of Premiums										78,049
Intangible Assets										16,665
Intangible Liabilities										9,190
University Commons [Member]
Business Acquisition [Line Items]
Date Purchased									Sep. 01, 2015
Property Name									University Commons
City/State									Boca Raton, FL
Property Type									Operating
Ownership											100.00%
Purchase Price									$ 80,500
Debt Assumed, Net of Premiums											$ 42,799
Intangible Assets									64,482
Intangible Liabilities											$ 14,039
Persimmon Place [Member]
Business Acquisition [Line Items]
Date Purchased								Jan. 31, 2014
Property Name								Persimmon Place
City/State								Dublin, CA
Property Type								Development
Ownership								100.00%
Purchase Price								$ 14,200
Debt Assumed, Net of Premiums								0
Intangible Assets								0
Intangible Liabilities								$ 0
Shops at Mira Vista [Member]
Business Acquisition [Line Items]
Date Purchased							Feb. 14, 2014
Property Name							Shops at Mira Vista
City/State							Austin, TX
Property Type							Operating
Ownership							100.00%
Purchase Price							$ 22,500
Debt Assumed, Net of Premiums							319
Intangible Assets							2,329
Intangible Liabilities							$ 291
Fairfield Portfolio [Member]
Business Acquisition [Line Items]
Date Purchased	[1]					Mar. 07, 2014
Property Name	[1]					Fairfield Portfolio (1)
City/State	[1]					Fairfield, CT
Property Type	[1]					Operating
Ownership						80.00%
Purchase Price	[1]					$ 149,344
Non-controlling interest recorded, fair value						$ 15,400
Number of real estate properties acquired | property						3
Debt Assumed, Net of Premiums	[1]					$ 77,730
Intangible Assets	[1]					12,650
Intangible Liabilities	[1]					$ 5,601
Willow Oaks Crossing [Member]
Business Acquisition [Line Items]
Date Purchased	[1]				Jun. 02, 2014
Property Name	[1]				Willow Oaks Crossing
City/State	[1]				Concord, NC
Property Type	[1]				Development
Ownership					100.00%
Purchase Price	[1]				$ 3,342
Debt Assumed, Net of Premiums	[1]				0
Intangible Assets	[1]				0
Intangible Liabilities	[1]				$ 0
Clybourn Commons [Member]
Business Acquisition [Line Items]
Date Purchased	[1]			Jul. 15, 2014
Property Name	[1]			Clybourn Commons
City/State	[1]			Chicago, IL
Property Type	[1]			Operating
Ownership				100.00%
Purchase Price	[1]			$ 19,000
Debt Assumed, Net of Premiums	[1]			0
Intangible Assets	[1]			1,686
Intangible Liabilities	[1]			$ 3,298
Belmont Chase [Member]
Business Acquisition [Line Items]
Date Purchased	[1]		Sep. 10, 2014
Property Name	[1]		Belmont Chase
City/State	[1]		Ashburn, VA
Property Type	[1]		Development
Ownership			100.00%
Purchase Price	[1]		$ 4,300
Debt Assumed, Net of Premiums	[1]		0
Intangible Assets	[1]		0
Intangible Liabilities	[1]		$ 0
City Line Market [Member]
Business Acquisition [Line Items]
Date Purchased	[1]	Sep. 19, 2014
Property Name	[1]	CityLine Market
City/State	[1]	Dallas, TX
Property Type	[1]	Development
Ownership		100.00%
Purchase Price	[1]	$ 4,913
Debt Assumed, Net of Premiums	[1]	0
Intangible Assets	[1]	0
Intangible Liabilities	[1]	$ 0
Partnership Interest [Member]
Business Acquisition [Line Items]
Payments for Deposits on Real Estate Acquisitions									2,250	0
Non-controlling interest recorded, fair value									0	15,385
Mortgage loans assumed for the acquisition of real estate									$ 42,799	$ 78,049

[1] On March 7, 2014, the Company acquired an 80% controlling interest in the Fairfield Portfolio, consisting of three operating properties. As a result of consolidation, the Company recorded the non-controlling interest of $15.4 million at fair value. The portfolio consists of three operating properties located in Fairfield, CT.