Real Estate Investments Business Acquisitions (Details) (USD $)	0 Months Ended	9 Months Ended
	Mar. 20, 2013	Sep. 30, 2013
Wholly Owned Properties [Member] | Preston Oaks [Member] [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition		May 30, 2013
Business Acquisition, Name of Acquired Entity		Preston Oaks
Equity Method Investments		100.00%
Mortgage loans assumed for the acquisition of real estate		$ 0
Business Acquisition Location, City and State		Dallas, TX
Business Acquisition, Description of Acquired Entity		N/A
Business Acquisition, Cost of Acquired Entity, Purchase Price		27,000,000
Acquired Finite-lived Intangible Asset, Amount		3,396,000
Acquired Finite Lived Intangible Liability, Amount		7,597,000
Consolidated Entities [Member] | Hilltop Village [Member]
Business Acquisition [Line Items]
Ownership	100.00%
Purchase Price		7,600,000
Unconsolidated Properties [Member] | Shoppes at Burnt Mills [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition		Jul. 23, 2013
Business Acquisition, Name of Acquired Entity		Shoppes of Burnt Mills
Equity Method Investments		20.00%
Mortgage loans assumed for the acquisition of real estate		7,496,000
Business Acquisition Location, City and State		Silver Springs, MD
Business Acquisition, Description of Acquired Entity		Columbia - Regency Partners II
Business Acquisition, Cost of Acquired Entity, Purchase Price		13,600,000
Acquired Finite-lived Intangible Asset, Amount		8,438,000
Acquired Finite Lived Intangible Liability, Amount		332,000
Macquarie Country Wide - Regency Iii, Llc [Member]
Business Acquisition [Line Items]
Equity Method Investments	24.95%
Fixed Rate Mortgage Loans [Member] | Consolidated Entities [Member] | Hilltop Village [Member]
Business Acquisition [Line Items]
Mortgage loans assumed for the acquisition of real estate		$ 7,500,000