SEGMENT REPORTING (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) segment	Mar. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	3
Revenues	$ 52,683	$ 52,481
Property operating expenses, other operating and real estate taxes	(11,993)	(16,143)
General and administrative expenses	(9,352)	(7,532)
Depreciation and amortization	(16,849)	(13,658)
Operating income	14,489	15,148
Equity in earnings of unconsolidated affiliates	1,954	6,593
Loss on debt extinguishment	0	(109)
Gain on disposition of properties	65,393	27,143
Interest and other finance expense	(8,038)	(8,821)
Income tax benefit (provision)	77	(1,417)
Net income	73,875	38,537
Net income attributable to noncontrolling interests	(44,950)	(21,990)
Net income attributable to Common Shareholders	28,925	16,547
Real Estate at Cost	2,746,214	2,504,302
Total Assets	3,148,327	2,870,866
Acquisition of Real Estate	12,287	220,271
Investment in Redevelopment and Improvements	37,463	40,494
Core Portfolio
Segment Reporting Information [Line Items]
Revenues	38,107	35,593
Property operating expenses, other operating and real estate taxes	(8,562)	(9,691)
General and administrative expenses	(9,073)	(6,811)
Depreciation and amortization	(13,495)	(9,907)
Operating income	6,977	9,184
Equity in earnings of unconsolidated affiliates	592	434
Loss on debt extinguishment		0
Gain on disposition of properties	0	0
Interest and other finance expense	(6,764)	(6,468)
Income tax benefit (provision)	77	(480)
Net income	882	2,670
Net income attributable to noncontrolling interests	(2,822)	(179)
Net income attributable to Common Shareholders	(1,940)	2,491
Real Estate at Cost	1,641,312	1,550,695
Total Assets	1,827,059	1,666,987
Acquisition of Real Estate	0	169,235
Investment in Redevelopment and Improvements	3,248	6,353
Funds
Segment Reporting Information [Line Items]
Revenues	9,938	13,480
Property operating expenses, other operating and real estate taxes	(3,431)	(6,452)
General and administrative expenses	(279)	(721)
Depreciation and amortization	(3,354)	(3,751)
Operating income	2,874	2,556
Equity in earnings of unconsolidated affiliates	1,362	6,159
Loss on debt extinguishment		(109)
Gain on disposition of properties	65,393	27,143
Interest and other finance expense	(1,274)	(2,353)
Income tax benefit (provision)	0	(937)
Net income	68,355	32,459
Net income attributable to noncontrolling interests	(42,128)	(21,811)
Net income attributable to Common Shareholders	26,227	10,648
Real Estate at Cost	1,104,902	953,607
Total Assets	1,166,589	1,105,319
Acquisition of Real Estate	12,287	51,036
Investment in Redevelopment and Improvements	34,215	34,141
Structured Financing Portfolio
Segment Reporting Information [Line Items]
Revenues	4,638	3,408
Property operating expenses, other operating and real estate taxes	0	0
General and administrative expenses	0	0
Depreciation and amortization	0	0
Operating income	4,638	3,408
Equity in earnings of unconsolidated affiliates	0	0
Loss on debt extinguishment		0
Gain on disposition of properties	0	0
Interest and other finance expense	0	0
Income tax benefit (provision)	0	0
Net income	4,638	3,408
Net income attributable to noncontrolling interests	0	0
Net income attributable to Common Shareholders	4,638	3,408
Real Estate at Cost	0	0
Total Assets	154,679	98,560
Acquisition of Real Estate	0	0
Investment in Redevelopment and Improvements	$ 0	$ 0