ACQUISITION OF REAL ESTATE AND DISCONTINUED OPERATIONS Acquisitions (Details) (USD $)	3 Months Ended
	Mar. 31, 2014 Core Portfolio sqft	Mar. 31, 2014 Fund IV sqft	Mar. 31, 2014 11 E Walton Chicago, IL Core Portfolio sqft	Mar. 31, 2014 61 Main Street Westport, CT Core Portfolio sqft	Mar. 31, 2014 865 W North Avenue Chicago, IL Core Portfolio sqft	Mar. 31, 2014 252-256 Greenwich Avenue Greenwich, CT Core Portfolio sqft	Mar. 31, 2014 Broughton Street Portfolio Savannah, GA Fund IV sqft	Mar. 31, 2014 Acquisitions In 2014 Purchase Price Allocations as Originally Reported	Dec. 31, 2013 Acquisitions in 2013 Purchase Price Allocations as Originally Reported	Mar. 31, 2014 Acquisitions in 2013 Adjustments	Mar. 31, 2014 Acquisitions in 2013 Finalized Purchase Price Allocations
Business Acquisition [Line Items]
Gross Leasable Area	35,310	55,565	6,738	3,400	16,000	9,172	55,565
Percent Owned			100.00%	100.00%	100.00%	100.00%	50.00%
Purchase Price	$ 90,600,000	$ 4,900,000	$ 44,000,000	$ 7,300,000	$ 14,800,000	$ 24,500,000	$ 4,900,000
Acquisition costs	700,000	400,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net
Land								23,865,000	22,182,000	(605,000)	21,577,000
Buildings and improvements								71,586,000	84,061,000	(7,514,000)	76,547,000
Acquisition-related intangible assets (in Acquired lease intangibles, net)									0	9,092,000	9,092,000
Acquisition-related intangible liabilities (in Acquired lease intangibles, net)									0	(973,000)	(973,000)
Total consideration								$ 95,451,000	$ 106,243,000	$ 0	$ 106,243,000