MORTGAGES PAYABLE Summary Mortgage Notes Payable (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended		12 Months Ended										12 Months Ended				12 Months Ended									12 Months Ended																											12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended		12 Months Ended								12 Months Ended		12 Months Ended		12 Months Ended
	Dec. 31, 2012 properties	Dec. 31, 2011	Dec. 31, 2012 Mortgages [Member]	Dec. 31, 2012 Mortgages [Member] Three Thirty River Street, Six Point Two Six Percent [Member]	Dec. 31, 2012 Mortgages [Member] Chicago Portfolio, Five Point Six Two Percent [Member]	Dec. 31, 2012 Mortgages [Member] Chicago Portfolio, Five Point Five Five Percent [Member]	Dec. 31, 2012 Mortgages [Member] Lincoln Park Centre LLC [Member]	Dec. 31, 2012 Mortgages [Member] West Diversity [Member]	Dec. 31, 2012 Mortgages [Member] Cortlandt Towne Center [Member]		Apr. 30, 2012 Mortgages [Member] Cortlandt Towne Center [Member]	Mar. 31, 2012 Mortgages [Member] Cortlandt Towne Center [Member]	Dec. 31, 2012 Mortgages [Member] Canarsie Plaza [Member]		Aug. 31, 2012 Mortgages [Member] Canarsie Plaza [Member]	Jul. 31, 2012 Mortgages [Member] Canarsie Plaza [Member]	Dec. 31, 2012 Mortgages [Member] Three Thirty River Street, Three Point Six Eight Percent [Member]	Dec. 31, 2012 Mortgages [Member] Tarrytown Shopping Center [Member]	Dec. 31, 2012 Mortgages [Member] Rhode Island Place Shopping Center [Member]	Dec. 31, 2012 Mortgages [Member] 640 Broadway [Member]	Dec. 31, 2012 Mortgages [Member] Atlantic Avenue [Member]	Dec. 31, 2012 Mortgages [Member] 125 Main Street Association [Member]	Dec. 31, 2012 Mortgages [Member] Citypoint, One Percent [Member]		Aug. 31, 2012 Mortgages [Member] Citypoint, One Percent [Member]	Dec. 31, 2012 Mortgages [Member] Heritage Shops [Member]	Dec. 31, 2012 Mortgages [Member] Citypoint, LIBOR Plus Three Point Three Percent [Member]		Dec. 31, 2012 Mortgages [Member] Fordham Place [Member]	Dec. 31, 2012 Mortgages [Member] 4401 White Plains [Member]	Dec. 31, 2012 Mortgages [Member] A and P Shipping Center [Member]	Dec. 31, 2012 Mortgages [Member] New Hyde Park Shopping Center [Member]	Dec. 31, 2012 Mortgages [Member] Six Self-Storage Properties [Member]	Dec. 31, 2012 Mortgages [Member] 639 West Diversey [Member]	Dec. 31, 2012 LIBOR [Member] Mortgages [Member] West Diversity [Member]	Dec. 31, 2012 LIBOR [Member] Mortgages [Member] Cortlandt Towne Center [Member]		Dec. 31, 2012 LIBOR [Member] Mortgages [Member] Canarsie Plaza [Member]		Dec. 31, 2012 LIBOR [Member] Mortgages [Member] 640 Broadway [Member]	Dec. 31, 2012 LIBOR [Member] Mortgages [Member] Atlantic Avenue [Member]	Dec. 31, 2012 LIBOR [Member] Mortgages [Member] Heritage Shops [Member]	Dec. 31, 2012 LIBOR [Member] Mortgages [Member] Citypoint, LIBOR Plus Three Point Three Percent [Member]		Dec. 31, 2012 LIBOR [Member] Mortgages [Member] Fordham Place [Member]	Dec. 31, 2012 LIBOR [Member] Mortgages [Member] 4401 White Plains [Member]	Dec. 31, 2012 LIBOR [Member] Mortgages [Member] New Hyde Park Shopping Center [Member]	Dec. 31, 2012 LIBOR [Member] Mortgages [Member] Six Self-Storage Properties [Member]	Dec. 31, 2012 Variable Interest Rate [Member]	Dec. 31, 2011 Variable Interest Rate [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] 161st Street [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] 161st Street [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] West Diversity [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] West Diversity [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] Cortlandt Towne Center [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] Cortlandt Towne Center [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] 640 Broadway [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] 640 Broadway [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] Heritage Shops [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] Heritage Shops [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] Fordham Place [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] Fordham Place [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] 4401 White Plains [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] 4401 White Plains [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] New Hyde Park Shopping Center [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] New Hyde Park Shopping Center [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] Village Commons Shopping Center [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] Village Commons Shopping Center [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] CityPoint [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] CityPoint [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] Pelham Manor [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] Pelham Manor [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] Branch Shopping Plaza [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Mortgage Notes Payable - Variable-Rate [Member] Branch Shopping Plaza [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Secured Credit Facilities - Variable-Rate [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Secured Credit Facilities - Variable-Rate [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Interest Rate Swap [Member]		Dec. 31, 2011 Variable Interest Rate [Member] Interest Rate Swap [Member]		Dec. 31, 2012 Variable Interest Rate [Member] Fund III [Member] Secured Credit Facilities - Variable-Rate [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Fund III [Member] Secured Credit Facilities - Variable-Rate [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Six Core Portfolio properties[Member] Secured Credit Facilities - Variable-Rate [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Six Core Portfolio properties[Member] Secured Credit Facilities - Variable-Rate [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Fund II term loan [Member] Secured Credit Facilities - Variable-Rate [Member]	Dec. 31, 2011 Variable Interest Rate [Member] Fund II term loan [Member] Secured Credit Facilities - Variable-Rate [Member]	Dec. 31, 2012 Variable Interest Rate [Member] Fund IV [Member] Secured Credit Facilities - Variable-Rate [Member]		Dec. 31, 2011 Variable Interest Rate [Member] Fund IV [Member] Secured Credit Facilities - Variable-Rate [Member]		Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Lincoln Park Centre LLC [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Lincoln Park Centre LLC [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Rhode Island Place Shopping Center [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Rhode Island Place Shopping Center [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Citypoint, One Percent [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Citypoint, One Percent [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] 639 West Diversey [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] 639 West Diversey [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] CityPoint [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] CityPoint [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Clark Diversey [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Clark Diversey [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] New Louden Center [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] New Louden Center [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Crescent Plaza [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Crescent Plaza [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Pacesetter Park Shopping Center [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Pacesetter Park Shopping Center [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Elmwood Park Shopping Center [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Elmwood Park Shopping Center [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Chicago Street Retail Portfolio [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Chicago Street Retail Portfolio [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] The Gateway Shopping Center [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] The Gateway Shopping Center [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Acadia Cambridge [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Acadia Cambridge [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] River Street [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] River Street [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Walnut Hill Plaza [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Walnut Hill Plaza [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] 239 Greenwich Avenue [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] 239 Greenwich Avenue [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Merrillville Plaza [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] Merrillville Plaza [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] 216th Street [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] 216th Street [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] AP Shopping Plaza [Member]	Dec. 31, 2011 Fixed Interest Rate [Member] Mortgage Notes Payable - Fixed Rate [Member] AP Shopping Plaza [Member]	Dec. 31, 2012 Fixed Interest Rate [Member] Interest Rate Swap [Member]		Dec. 31, 2011 Fixed Interest Rate [Member] Interest Rate Swap [Member]		Aug. 31, 2012 Mortgages Payable [Member] Mortgages [Member] Citypoint, One Percent [Member]	Aug. 31, 2012 Affiliated Entity [Member] Mortgages [Member] Citypoint, One Percent [Member]
Debt Instrument [Line Items]
Mortgages Payable	$ 727,100	$ 647,739
Mortgages payable	727,048	647,739									74,000	50,000			69,600	56,500									20,000																								292,886	359,950	332,693	239,898	28,900	28,900	15,273	0	73,499	50,000	22,750	0	21,000	0	82,205	84,277	6,381	0	6,484	0	9,192	9,310	20,650	20,650	33,833	34,000	12,526	12,761	93,050	177,079	(132,857)	[1]	(57,027)	[1]	0	136,079	0	1,000	0	40,000	93,050	[2]	0	[2]	434,269	287,756	19,478	0	16,426	0	5,262	0	4,431	0	20,000	20,000	4,345	4,491	13,634	13,882	17,025	17,287	11,742	11,941	33,258	33,738	15,835	0	20,036	20,308	6,931	0	4,197	0	23,194	23,458	26,000	26,000	26,151	26,250	25,500	25,500	7,967	7,874	132,857	[1]	57,027	[1]	5,200	14,800
Number of Properties Collateralized	35
Interest rate, minimum	1.00%
Interest rate, maximum	7.25%
Proceeds from Issuance of Long-term Debt			454,375	7,022	14,490	1,538	19,763	15,500	24,005	[3]			13,124	[4]			4,250	0	16,510	22,750	10,600	0	5,262	[5]		21,000	50,000	[6]	83,261	6,400	8,000	6,500	120,000	4,400
Debt Instrument, Interest Rate, Stated Percentage				6.26%	5.62%	5.55%	5.85%										3.68%		6.35%				1.00%	[5]							4.20%			6.65%
Debt Instrument, Description of Variable Rate Basis																																			LIBOR	LIBOR	[3]	LIBOR	[4]	LIBOR	LIBOR	LIBOR	LIBOR	[6]	LIBOR	LIBOR	LIBOR	LIBOR					LIBOR		LIBOR		LIBOR		LIBOR		LIBOR		LIBOR		LIBOR		LIBOR		LIBOR		LIBOR		LIBOR		LIBOR								LIBOR		LIBOR		LIBOR
Debt Instrument, Basis Spread on Variable Rate																																			1.90%	1.90%	[3]	2.25%	[4]	2.95%	3.35%	2.25%	3.30%	[6]	3.00%	1.90%	2.25%	2.15%					5.50%		1.90%		1.90%		2.95%		2.25%		3.00%		1.90%		2.25%		1.40%		2.50%		2.75%		2.25%								2.25%		1.25%		2.90%
Repayments of debt			364,423	0	0	0	0	0	0	[3]			68,644	[4]			0	8,260	0	0	22,100	12,500	0	[5]		0	0	[6]	83,261	0	7,763	0	161,895	0
Interest rate at December 31, 2011																																																					5.71%		2.11%		2.11%		3.16%		2.46%		3.21%		2.11%		2.46%		1.61%		2.71%		2.96%		2.46%								2.46%		1.46%		3.11%								5.85%		6.35%		1.00%		6.65%		7.25%		6.35%		5.64%		4.98%		5.12%		5.53%		5.55%		5.44%		6.26%		3.68%		6.06%		5.42%		5.88%		5.80%		4.20%		5.41%	[1]
Unamortized premium	$ (107)	$ 33

[1] Represents the amount of the Company’s variable-rate debt that has been fixed through certain cash flow hedge transactions (Note 10).

[2] The Fund IV revolving subscription line of credit is secured by unfunded investor capital commitments.

[3] Loan was amended from $50.0 million to $74.0 million.

[4] Loan was amended from $56.5 million to $69.6 million.

[5] The Company entered into a $20.0 million loan under the New Markets Tax Credit program to finance the construction of this property. Of the total principal, $14.8 million is due to an affiliate included in the consolidated group which has been netted on the accompanying balance sheet and the resulting $5.2 million is included in Mortgages Payable in the accompanying consolidated balance sheet at December 31, 2012.

[6] As of December 31, 2012 no funds have been drawn down on this construction loan.