ACQUISITION AND DISPOSITION OF REAL ESTATE AND PROPERTIES HELD FOR SALE - Dispositions (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($) ft² properties property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gross leasable area (in square feet) | ft²	695,168
Sale Price	$ 327,903
Gain on Sale	$ 113,106
Number of retail properties (in properties) | property	142
Lincoln Park Centre
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gross leasable area (in square feet) | ft²	61,761
Sale Price	$ 64,000
Gain on Sale	$ 27,143
White City
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gross leasable area (in square feet) | ft²	249,549
Sale Price	$ 96,750
Gain on Sale	$ 17,105
City Point
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gross leasable area (in square feet) | ft²	0
Sale Price	$ 115,600
Gain on Sale	$ 49,884
Liberty Avenue
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gross leasable area (in square feet) | ft²	26,117
Sale Price	$ 24,000
Gain on Sale	$ 11,957
Parkway Crossing
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gross leasable area (in square feet) | ft²	260,241
Sale Price	$ 27,275
Gain on Sale	$ 6,938
Kroger-Safeway
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gross leasable area (in square feet) | ft²	97,500
Sale Price	$ 278
Gain on Sale	$ 79
Number of ground leases terminated (in properties) | properties	2
Number of retail properties (in properties) | properties	3