SEGMENT REPORTING Income Statement (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014 segment	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Number of reportable segments									3
Revenues	$ 51,156	$ 47,660	$ 49,511	$ 46,685	$ 44,102	$ 41,085	$ 40,808	$ 42,291	$ 195,012	$ 168,286	$ 114,987
Property operating expenses, other operating and real estate taxes									(51,671)	(46,553)	(37,716)
Reserve for notes receivable									0	0	(405)
General and administrative expenses									(27,433)	(25,555)	(21,223)
Depreciation and amortization									(49,645)	(40,299)	(27,888)
Operating income									66,263	55,879	27,755
Equity in (losses) earnings of unconsolidated affiliates									8,723	12,382	550
Gain on disposition of properties of unconsolidated affiliates									102,855	0	3,061
Impairment of unconsolidated affiliates									0	0	(2,032)
Impairment of asset									0	(1,500)	0
Loss on debt extinguishment									(335)	(765)	(198)
Gain on involuntary conversion of asset									0	0	2,368
Interest and other finance expense									(39,091)	(39,474)	(22,811)
Gain on disposition of property									13,138	0	0
Income tax (provision) benefit									(629)	(19)	574
Income from continuing operations									150,924	26,503	9,267
Discontinued operations
Operating income from discontinued operations									0	6,818	12,007
Impairment of asset									0	(6,683)	0
Loss on debt extinguishment									0	(800)	(2,541)
Gain on disposition of properties									1,222	18,802	71,203
Income from discontinued operations									1,222	18,137	80,669
Net income									152,146	44,640	89,936
Noncontrolling interests
Income from continuing operations									(80,059)	7,523	14,352
Income from discontinued operations									(1,023)	(12,048)	(64,582)
Net income attributable to noncontrolling interests									(81,082)	(4,525)	(50,230)
Net income attributable to Common Shareholders	9,441	28,564	11,464	21,595	12,251	9,484	8,757	9,623	71,064	40,115	39,706
Core Portfolio [Member]
Segment Reporting Information [Line Items]
Revenues									125,022	110,355	70,400
Property operating expenses, other operating and real estate taxes									(33,097)	(29,040)	(21,817)
Reserve for notes receivable											0
General and administrative expenses									(24,853)	(24,387)	(19,578)
Depreciation and amortization									(35,875)	(28,989)	(17,065)
Operating income									31,197	27,939	11,940
Equity in (losses) earnings of unconsolidated affiliates									(77)	(99)	262
Gain on disposition of properties of unconsolidated affiliates									0		0
Impairment of unconsolidated affiliates											0
Impairment of asset										(1,500)
Loss on debt extinguishment									(3)	(309)	0
Gain on involuntary conversion of asset											2,368
Interest and other finance expense									(27,021)	(26,158)	(15,431)
Gain on disposition of property									12,577
Income tax (provision) benefit									(176)	131	(241)
Income from continuing operations									16,497	4	(1,102)
Discontinued operations
Operating income from discontinued operations										535	319
Impairment of asset										0
Loss on debt extinguishment										(145)	0
Gain on disposition of properties									0	6,488	0
Income from discontinued operations									0	6,878	319
Net income									16,497	6,882	(783)
Noncontrolling interests
Income from continuing operations									(3,213)	(1,002)	60
Income from discontinued operations									(9)	(2,406)	(128)
Net income attributable to noncontrolling interests									(3,222)	(3,408)	(68)
Net income attributable to Common Shareholders									13,275	3,474	(851)
Opportunity Funds [Member]
Segment Reporting Information [Line Items]
Revenues									54,659	46,131	36,560
Property operating expenses, other operating and real estate taxes									(18,574)	(17,513)	(15,899)
Reserve for notes receivable											0
General and administrative expenses									(1,665)	(1,168)	(1,645)
Depreciation and amortization									(13,770)	(11,310)	(10,823)
Operating income									20,650	16,140	8,193
Equity in (losses) earnings of unconsolidated affiliates									8,800	12,481	288
Gain on disposition of properties of unconsolidated affiliates									102,855		3,061
Impairment of unconsolidated affiliates											(2,032)
Impairment of asset										0
Loss on debt extinguishment									(332)	(456)	(198)
Gain on involuntary conversion of asset											0
Interest and other finance expense									(12,070)	(13,316)	(7,380)
Gain on disposition of property									561
Income tax (provision) benefit									(453)	(150)	815
Income from continuing operations									120,011	14,699	2,747
Discontinued operations
Operating income from discontinued operations										6,283	11,688
Impairment of asset										(6,683)
Loss on debt extinguishment										(655)	(2,541)
Gain on disposition of properties									1,222	12,314	71,203
Income from discontinued operations									1,222	11,259	80,350
Net income									121,233	25,958	83,097
Noncontrolling interests
Income from continuing operations									(76,846)	8,525	14,292
Income from discontinued operations									(1,014)	(9,642)	(64,454)
Net income attributable to noncontrolling interests									(77,860)	(1,117)	(50,162)
Net income attributable to Common Shareholders									43,373	24,841	32,935
Notes Receivable [Member]
Segment Reporting Information [Line Items]
Revenues									15,331	11,800	8,027
Property operating expenses, other operating and real estate taxes									0	0	0
Reserve for notes receivable											(405)
General and administrative expenses									(915)	0	0
Depreciation and amortization									0	0	0
Operating income									14,416	11,800	7,622
Equity in (losses) earnings of unconsolidated affiliates									0	0	0
Gain on disposition of properties of unconsolidated affiliates									0		0
Impairment of unconsolidated affiliates											0
Impairment of asset										0
Loss on debt extinguishment									0	0	0
Gain on involuntary conversion of asset											0
Interest and other finance expense									0	0	0
Gain on disposition of property									0
Income tax (provision) benefit									0	0	0
Income from continuing operations									14,416	11,800	7,622
Discontinued operations
Operating income from discontinued operations										0	0
Impairment of asset										0
Loss on debt extinguishment										0	0
Gain on disposition of properties									0	0	0
Income from discontinued operations									0	0	0
Net income									14,416	11,800	7,622
Noncontrolling interests
Income from continuing operations									0	0	0
Income from discontinued operations									0	0	0
Net income attributable to noncontrolling interests									0	0	0
Net income attributable to Common Shareholders									$ 14,416	$ 11,800	$ 7,622