MORTGAGES AND OTHER NOTES PAYABLE Mortgage Loan Activity (Details) (USD $)	12 Months Ended		1 Months Ended
	Dec. 31, 2014 property		Dec. 31, 2014		Apr. 30, 2014	Feb. 28, 2014	Jan. 31, 2014	Mar. 31, 2014	May 31, 2014	Jun. 30, 2014	Oct. 31, 2014	Dec. 31, 2013	Jul. 31, 2014
Debt Instrument [Line Items]
Mortgages and other notes payable	$ 1,127,600,000		1,127,600,000									$ 1,038,100,000
Number of properties collateralized	40		40
Interest rate, minimum	1.00%
Interest rate, maximum	6.65%
LIBOR [Member]
Debt Instrument [Line Items]
Borrowings, interest rate description			LIBOR		LIBOR	LIBOR
Mortgages [Member]
Debt Instrument [Line Items]
Borrowings, amount	301,188,000		301,188,000
Repayments of debt	86,100,000
Mortgages [Member] | 664 N. Michigan [Member] | LIBOR plus 1.65% Mortgage Note [Member]
Debt Instrument [Line Items]
Borrowings, amount							45,000,000
Mortgages [Member] | 664 N. Michigan [Member] | LIBOR plus 1.65% Mortgage Note [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Borrowings, interest rate description							LIBOR
Borrowings, interest rate basis spread							1.65%
Mortgages [Member] | New Hyde Park Shopping Center [Member] | LIBOR Plus 2.25% Mortgage Note [Member]
Debt Instrument [Line Items]
Borrowings, amount							1,500,000
Repayments of debt					7,700,000
Mortgages [Member] | New Hyde Park Shopping Center [Member] | LIBOR Plus 2.25% Mortgage Note [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Borrowings, interest rate description							LIBOR
Borrowings, interest rate basis spread					2.25%		2.25%
Mortgages [Member] | New Hyde Park Shopping Center [Member] | LIBOR Plus 1.85% Mortgage Note [Member]
Debt Instrument [Line Items]
Borrowings, amount					12,000,000
Mortgages [Member] | New Hyde Park Shopping Center [Member] | LIBOR Plus 1.85% Mortgage Note [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Borrowings, interest rate description					LIBOR
Borrowings, interest rate basis spread					1.85%
Mortgages [Member] | Heritage [Member] | LIBOR Plus 2.25% Mortgage Note [Member]
Debt Instrument [Line Items]
Repayments of debt						20,900,000
Mortgages [Member] | Heritage [Member] | LIBOR Plus 2.25% Mortgage Note [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Borrowings, interest rate basis spread						2.25%
Mortgages [Member] | Heritage [Member] | LIBOR Plus 1.55% Mortgage Note [Member]
Debt Instrument [Line Items]
Borrowings, amount						24,500,000
Mortgages [Member] | Heritage [Member] | LIBOR Plus 1.55% Mortgage Note [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Borrowings, interest rate description						LIBOR
Borrowings, interest rate basis spread						1.55%
Mortgages [Member] | 654 Broadway [Member] | LIBOR Plus 1.88% Mortgage Note [Member] [Member]
Debt Instrument [Line Items]
Borrowings, amount								9,000,000
Mortgages [Member] | 654 Broadway [Member] | LIBOR Plus 1.88% Mortgage Note [Member] [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Borrowings, interest rate description								LIBOR
Borrowings, interest rate basis spread								1.88%
Mortgages [Member] | Paramus Plaza [Member] | LIBOR Plus 1.70% Percent Mortgage Note [Member]
Debt Instrument [Line Items]
Borrowings, amount								12,600,000
Mortgages [Member] | Paramus Plaza [Member] | LIBOR Plus 1.70% Percent Mortgage Note [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Borrowings, interest rate description								LIBOR
Borrowings, interest rate basis spread								1.70%
Mortgages [Member] | 613 - 623 W. Diversey [Member] | 6.35% Mortgage Note [Member]
Debt Instrument [Line Items]
Borrowings, amount					0
Borrowings, interest rate					6.35%
Repayments of debt					4,200,000
Mortgages [Member] | Lake Montclair [Member] | LIBOR Plus 2.15% Mortgage Note [Member]
Debt Instrument [Line Items]
Borrowings, amount					15,500,000
Mortgages [Member] | Lake Montclair [Member] | LIBOR Plus 2.15% Mortgage Note [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Borrowings, interest rate description					LIBOR
Borrowings, interest rate basis spread					2.15%
Mortgages [Member] | 938 W. North Avenue [Member] | LIBOR Plus 2.35% Mortgage Note [Member]
Debt Instrument [Line Items]
Borrowings, amount									12,500,000
Mortgages [Member] | 938 W. North Avenue [Member] | LIBOR Plus 2.35% Mortgage Note [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Borrowings, interest rate description									LIBOR
Borrowings, interest rate basis spread									2.35%
Mortgages [Member] | 1151 Third Avenue [Member] | LIBOR Plus 1.75% Mortgage Note [Member]
Debt Instrument [Line Items]
Borrowings, amount										12,500,000
Mortgages [Member] | 1151 Third Avenue [Member] | LIBOR Plus 1.75% Mortgage Note [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Borrowings, interest rate description										LIBOR
Borrowings, interest rate basis spread										1.75%
Mortgages [Member] | New Loudon Center [Member] | 5.64% Mortgage Note [Member]
Debt Instrument [Line Items]
Borrowings, amount										0
Borrowings, interest rate										5.64%
Repayments of debt										13,300,000
Mortgages [Member] | Bedford Green [Member] | 5.95% Mortgage Note [Member]
Debt Instrument [Line Items]
Borrowings, amount													29,794,000
Borrowings, interest rate													5.10%
Mortgages [Member] | City Point [Member]
Debt Instrument [Line Items]
Borrowings, amount	81,191,000	[1]	81,191,000	[1]
Mortgages [Member] | City Point [Member] | LIBOR Plus 1.70% Percent Mortgage Note [Member]
Debt Instrument [Line Items]
Borrowings, amount	20,000,000		20,000,000
Mortgages [Member] | City Point [Member] | LIBOR Plus 1.70% Percent Mortgage Note [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Borrowings, interest rate description			LIBOR
Borrowings, interest rate basis spread			1.70%
Mortgages [Member] | City Point [Member] | LIBOR Plus 2.00% Mortgage Note [Member]
Debt Instrument [Line Items]
Borrowings, amount											20,000,000
Mortgages [Member] | City Point [Member] | LIBOR Plus 2.00% Mortgage Note [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Borrowings, interest rate description											LIBOR
Borrowings, interest rate basis spread											2.00%
Mortgages [Member] | City Point [Member] | 7.25% Mortgage Loan [Member]
Debt Instrument [Line Items]
Borrowings, interest rate											7.25%
Repayments of debt											20,000,000
Mortgages [Member] | City Point [Member] | LIBOR Plus 5.00% Mortgage Loan [Member]
Debt Instrument [Line Items]
Repayments of debt			20,000,000
Mortgages [Member] | City Point [Member] | LIBOR Plus 5.00% Mortgage Loan [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Borrowings, interest rate basis spread			5.00%
Mortgages [Member] | Lincoln Park Center [Member]
Debt Instrument [Line Items]
Borrowings, amount	5,000,000		5,000,000
Mortgages [Member] | 3104 M Street [Member] | Prime Plus .50% Mortgage Note [Member]
Debt Instrument [Line Items]
Borrowings, amount	103,000		103,000
Mortgages [Member] | 3104 M Street [Member] | Prime Plus .50% Mortgage Note [Member] | Prime [Member]
Debt Instrument [Line Items]
Borrowings, interest rate description			PRIME
Borrowings, interest rate basis spread			0.50%
Construction Loans [Member] | City Point [Member]
Debt Instrument [Line Items]
Construction loan, amount released into restricted cash	199,000,000		199,000,000
Construction loan, amount withdrawn from restricted cash	168,400,000		168,400,000
Construction loan, amount released into restricted cash, amount available	$ 30,600,000		30,600,000

[1] As of December 31, 2014, $199.0 million of funds have been released under the Company's EB-5 loan relating to its City Point project into a restricted cash account. $168.4 million has been drawn to fund construction activities, with $30.6 million remaining in the restricted cash account at December 31, 2014.