Real Estate (Significant Acquisitions and Dispositions) (Details) $ in Thousands								3 Months Ended		6 Months Ended	12 Months Ended			24 Months Ended
	Nov. 19, 2015 USD ($)	Oct. 01, 2015 USD ($) ft²	Jul. 08, 2015 USD ($)	May. 04, 2015 USD ($) ft²	Apr. 24, 2015 USD ($)	Jan. 09, 2015 USD ($) ft² shares	Jan. 02, 2014 USD ($) ft²	Dec. 31, 2015 USD ($)	Jun. 30, 2015 USD ($)	Dec. 16, 2015 USD ($) building	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Feb. 25, 2015 USD ($)
Business Acquisition and Disposition [Line Items]
Mortgage loans assumed with acquisition											$ 89,516	$ 68,282	$ 0
Contributions from noncontrolling interests											34,737	65,350
Gain on sale of real estate											28,330	4,401	4,994
Houston Street
Business Acquisition and Disposition [Line Items]
Proceeds from sale					$ 46,100
Gain on sale of real estate					$ 11,500				$ 11,500
Courtyard Shops
Business Acquisition and Disposition [Line Items]
Proceeds from sale	$ 52,800
Gain on sale of real estate	$ 16,800							$ 16,800
San Antonio Center
Business Acquisition and Disposition [Line Items]
Square footage of real estate property | ft²						376,000
Gross value						$ 62,200
Mortgage loans assumed with acquisition						$ 18,700
Number of downREIT Operating Partnership Units Issued in Connection with Business Acquisition | shares						58,000
Cash paid in acquisition						$ 27,000
Contributions from noncontrolling interests						$ 16,300
Effective interest percentage						80.00%
CocoWalk
Business Acquisition and Disposition [Line Items]
Square footage of real estate property | ft²				198,000
Purchase Price				$ 87,500
Contributions from noncontrolling interests				6,900
The Shops at Sunset Place
Business Acquisition and Disposition [Line Items]
Square footage of real estate property | ft²		515,000
Mortgage loans assumed with acquisition		$ 70,800
Purchase Price		110,200
Contributions from noncontrolling interests		6,300
The Grove at Shrewsbury
Business Acquisition and Disposition [Line Items]
Square footage of real estate property | ft²							187,000
Brook 35
Business Acquisition and Disposition [Line Items]
Square footage of real estate property | ft²							99,000
Grove at Shrewsbury and Brook 35
Business Acquisition and Disposition [Line Items]
Gross value							$ 161,000
Effective economic interest percentage							84.00%
Mortgage loans assumed with acquisition							$ 68,000
Number of downREIT operating partnership units							632,000
Cash paid in acquisition							$ 13,000
Net assets acquired allocated to below market leases							2,300
Contributions from noncontrolling interests							71,100
Acquisition costs												$ 1,000	$ 1,000		$ 2,000
Above Market Leases | Grove at Shrewsbury and Brook 35
Business Acquisition and Disposition [Line Items]
Net assets acquired allocated to above market leases							$ 1,700
Other Liabilities | San Antonio Center
Business Acquisition and Disposition [Line Items]
Net assets acquired allocated to below market leases						$ 19,100
Other Liabilities | CocoWalk
Business Acquisition and Disposition [Line Items]
Net assets acquired allocated to below market leases				4,300
Other Liabilities | The Shops at Sunset Place
Business Acquisition and Disposition [Line Items]
Net assets acquired allocated to below market leases		6,600
Other Assets | Above Market Leases | San Antonio Center
Business Acquisition and Disposition [Line Items]
Net assets acquired allocated to above market leases						$ 8,100
Other Assets | Above Market Leases | CocoWalk
Business Acquisition and Disposition [Line Items]
Net assets acquired allocated to above market leases				$ 1,500
Other Assets | Above Market Leases | The Shops at Sunset Place
Business Acquisition and Disposition [Line Items]
Net assets acquired allocated to above market leases		$ 4,800
General and Administrative Expense | San Antonio Center
Business Acquisition and Disposition [Line Items]
Acquisition costs											1,100			$ 1,800
General and Administrative Expense | CocoWalk
Business Acquisition and Disposition [Line Items]
Acquisition costs											1,100
General and Administrative Expense | The Shops at Sunset Place
Business Acquisition and Disposition [Line Items]
Acquisition costs											$ 900
CocoWalk | Coconut Grove
Business Acquisition and Disposition [Line Items]
Purchase Price										$ 7,800
Number Of Buildings | building										8
Land | Pike Seven Plaza
Business Acquisition and Disposition [Line Items]
Purchase Price			$ 5,000
The Grove at Shrewsbury (East)
Business Acquisition and Disposition [Line Items]
Price to acquire non controlling interest																$ 8,800
CocoWalk
Business Acquisition and Disposition [Line Items]
Common interest percentage				80.00%
The Shops at Sunset Place
Business Acquisition and Disposition [Line Items]
Common interest percentage		85.00%