ACQUISITION AND DISPOSITION OF PROPERTIES AND DISCONTINUED OPERATIONS Discontinued Operations (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		1 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011 Fifteen Kroger/Safeway Locations [Member] leasehold_interests	Oct. 31, 2011 Columbus Ohio [Member] Granville Centre [Member] sqft	May 31, 2011 Ledgewood New Jersey [Member] Ledgewood Mall [Member] sqft	Jan. 31, 2011 Oak Brook Illinois [Member] Oakbrook Center [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Leasehold Interests Sold (in leasehold interests)			15
Sales Price	$ 0	$ 7,977	$ 17,500	$ 2,300	$ 37,000	$ 8,200
Gain (Loss)	$ 0	$ 3,922				$ 3,900
Square Footage of Real Estate Property (in square feet)				135,000	517,000