SEGMENT REPORTING (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) segment	Jun. 30, 2014 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment			3
Revenues	$ 53,161	$ 49,511	$ 105,642	$ 96,196
Property operating expenses, other operating and real estate taxes	(13,214)	(12,214)	(29,357)	(25,695)
General and administrative expenses	(8,005)	(6,879)	(15,537)	(13,775)
Depreciation and amortization	(13,903)	(11,584)	(27,561)	(23,171)
Operating income	13,039	18,834	28,187	33,555
Equity in earnings of unconsolidated affiliates	3,406	1,430	9,999	4,459
Gain on disposition of property of unconsolidated affiliates	17,105	0	17,105	0
Loss on debt extinguishment	(25)	(66)	(134)	(269)
Impairment of asset	(5,000)	0	(5,000)	0
Gain on disposition of properties	61,841	561	88,984	12,948
Interest and other finance expense	(9,964)	(9,534)	(18,785)	(20,185)
Income tax benefit (provision)	56	83	(1,361)	(85)
Income from continuing operations	85,458	11,308	123,995	30,423
Net income	85,458	11,868	123,995	30,983
Gain on disposition of property	0	560	0	560
Continuing operations	(58,963)	57	(80,953)	2,537
Discontinued operations	0	(461)	0	(461)
Net loss (income) attributable to noncontrolling interests	(58,963)	(404)	(80,953)	2,076
Net income attributable to Common Shareholders	26,495	11,464	43,042	33,059
Real Estate at Cost	2,578,580	1,982,629	2,578,580	1,982,629
Total Assets	2,973,699	2,372,196	2,973,699	2,372,196
Acquisition of Real Estate	52,800	17,100	273,071	107,600
Investment in Redevelopment and Improvements	64,751	30,806	105,245	68,311
Core Portfolio
Segment Reporting Information [Line Items]
Revenues	37,593	30,535	73,186	60,684
Property operating expenses, other operating and real estate taxes	(8,235)	(7,587)	(17,926)	(15,493)
General and administrative expenses	(7,397)	(6,238)	(14,208)	(12,651)
Depreciation and amortization	(10,568)	(8,300)	(20,475)	(16,633)
Operating income	6,393	8,410	15,577	15,907
Equity in earnings of unconsolidated affiliates	699	227	1,133	323
Gain on disposition of property of unconsolidated affiliates	0		0
Loss on debt extinguishment	0	(3)	0	(3)
Impairment of asset	(5,000)		(5,000)
Gain on disposition of properties	0	0	0	12,387
Interest and other finance expense	(7,329)	(6,627)	(13,797)	(13,510)
Income tax benefit (provision)	75	91	(405)	(13)
Income from continuing operations		2,098		15,091
Net income	(162)	2,098	2,508	15,091
Gain on disposition of property		0		0
Continuing operations		(1,036)		(1,453)
Discontinued operations		(4)		(4)
Net loss (income) attributable to noncontrolling interests	2,205	(1,040)	2,026	(1,457)
Net income attributable to Common Shareholders	2,043	1,058	4,534	13,634
Real Estate at Cost	1,553,174	1,184,956	1,553,174	1,184,956
Total Assets	1,650,555	1,153,586	1,650,555	1,153,586
Acquisition of Real Estate	0	17,100	169,235	107,600
Investment in Redevelopment and Improvements	3,271	754	9,624	2,182
Funds
Segment Reporting Information [Line Items]
Revenues	11,583	13,934	25,063	26,576
Property operating expenses, other operating and real estate taxes	(4,979)	(4,627)	(11,431)	(10,202)
General and administrative expenses	(608)	(641)	(1,329)	(1,124)
Depreciation and amortization	(3,335)	(3,284)	(7,086)	(6,538)
Operating income	2,661	5,382	5,217	8,712
Equity in earnings of unconsolidated affiliates	2,707	1,203	8,866	4,136
Gain on disposition of property of unconsolidated affiliates	17,105		17,105
Loss on debt extinguishment	(25)	(63)	(134)	(266)
Impairment of asset	0		0
Gain on disposition of properties	61,841	561	88,984	561
Interest and other finance expense	(2,635)	(2,907)	(4,988)	(6,675)
Income tax benefit (provision)	(19)	(8)	(956)	(72)
Income from continuing operations		4,168		6,396
Net income	81,635	4,728	114,094	6,956
Gain on disposition of property		560		560
Continuing operations		1,093		3,990
Discontinued operations		(457)		(457)
Net loss (income) attributable to noncontrolling interests	(61,168)	636	(82,979)	3,533
Net income attributable to Common Shareholders	20,467	5,364	31,115	10,489
Real Estate at Cost	1,025,406	797,673	1,025,406	797,673
Total Assets	1,154,213	1,122,303	1,154,213	1,122,303
Acquisition of Real Estate	52,800	0	103,836	0
Investment in Redevelopment and Improvements	61,480	30,052	95,621	66,129
Structured Financing
Segment Reporting Information [Line Items]
Revenues	3,985	5,042	7,393	8,936
Property operating expenses, other operating and real estate taxes	0	0	0	0
General and administrative expenses	0	0	0	0
Depreciation and amortization	0	0	0	0
Operating income	3,985	5,042	7,393	8,936
Equity in earnings of unconsolidated affiliates	0	0	0	0
Gain on disposition of property of unconsolidated affiliates	0		0
Loss on debt extinguishment	0	0	0	0
Impairment of asset	0		0
Gain on disposition of properties	0	0	0	0
Interest and other finance expense	0	0	0	0
Income tax benefit (provision)	0	0	0	0
Income from continuing operations		5,042		8,936
Net income	3,985	5,042	7,393	8,936
Gain on disposition of property		0		0
Continuing operations		0		0
Discontinued operations		0		0
Net loss (income) attributable to noncontrolling interests	0	0	0	0
Net income attributable to Common Shareholders	3,985	5,042	7,393	8,936
Real Estate at Cost	0	0	0	0
Total Assets	168,931	96,307	168,931	96,307
Acquisition of Real Estate	0	0	0	0
Investment in Redevelopment and Improvements	$ 0	$ 0	$ 0	$ 0