SEGMENT INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 31, 2012	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 segment	Sep. 30, 2011	Dec. 31, 2011
SEGMENT INFORMATION
Number of reportable business segments				3
Revenues:
Rental income		$ 310,910	$ 261,368	$ 876,592	$ 540,133
Resident fees and services		317,131	274,294	906,946	590,103
Medical office building and other services revenue		4,544	9,271	16,791	26,050
Income from loans and investments		9,035	10,072	25,223	24,548
Interest and other income		330	373	441	529
Total revenues		641,950	555,378	1,825,993	1,181,363
Less:
Interest and other income		330	373	441	529
Property-level operating expenses		253,005	207,427	706,544	438,386
Medical office building services costs		1,487	6,347	8,314	19,837
Segment NOI		387,128	341,231	1,110,694	722,611
Income (loss) from unconsolidated entities	16,600	17,074	182	17,905	(71)
Segment profit		404,202	341,413	1,128,599	722,540
Interest and other income		330	373	441	529
Interest expense		(75,139)	(69,518)	(217,475)	(162,348)
Depreciation and amortization		(189,908)	(156,593)	(538,946)	(286,663)
General, administrative and professional fees		(26,872)	(20,624)	(75,779)	(51,010)
Gain (loss) on extinguishment of debt		1,194	(8,685)	(38,339)	(25,211)
Litigation proceeds, net		0	85,327	0	85,327
Merger-related expenses and deal costs		(4,917)	(69,350)	(49,566)	(131,606)
Other		(2,508)	(13,882)	(5,594)	(5,827)
Income tax benefit		8,886	13,732	2,727	23,039
Discontinued operations		(3,447)	(209)	69,581	1,994
Net income		111,821	101,984	275,649	170,764	363,261
Triple-Net Leased Properties
Revenues:
Rental income		210,096	203,209	622,702	433,980
Resident fees and services		0	0	0	0
Medical office building and other services revenue		1,110	1,109	3,329	1,109
Income from loans and investments		0	0	0	0
Total revenues		211,206	204,318	626,031	435,089
Less:
Property-level operating expenses		0	0	0	0
Medical office building services costs		0	0	0	0
Segment NOI		211,206	204,318	626,031	435,089
Income (loss) from unconsolidated entities		348	121	1,068	121
Segment profit		211,554	204,439	627,099	435,210
Senior Living Operations
Revenues:
Rental income		0	0	0	0
Resident fees and services		317,131	274,294	906,946	590,103
Medical office building and other services revenue		0	0	0	0
Income from loans and investments		0	0	0	0
Total revenues		317,131	274,294	906,946	590,103
Less:
Property-level operating expenses		216,861	187,356	620,075	401,361
Medical office building services costs		0	0	0	0
Segment NOI		100,270	86,938	286,871	188,742
Income (loss) from unconsolidated entities		0	0	0	0
Segment profit		100,270	86,938	286,871	188,742
MOB Operations
Revenues:
Rental income		100,814	58,159	253,890	106,153
Resident fees and services		0	0	0	0
Medical office building and other services revenue		3,434	8,162	13,462	24,941
Income from loans and investments		0	0	0	0
Total revenues		104,248	66,321	267,352	131,094
Less:
Property-level operating expenses		36,144	20,071	86,469	37,025
Medical office building services costs		1,487	6,347	8,314	19,837
Segment NOI		66,617	39,903	172,569	74,232
Income (loss) from unconsolidated entities		16,726	61	16,837	(192)
Segment profit		83,343	39,964	189,406	74,040
All Other
Revenues:
Rental income		0	0	0	0
Resident fees and services		0	0	0	0
Medical office building and other services revenue		0	0	0	0
Income from loans and investments		9,035	10,072	25,223	24,548
Interest and other income		330	373	441	529
Total revenues		9,365	10,445	25,664	25,077
Less:
Interest and other income		330	373	441	529
Property-level operating expenses		0	0	0	0
Medical office building services costs		0	0	0	0
Segment NOI		9,035	10,072	25,223	24,548
Income (loss) from unconsolidated entities		0	0	0	0
Segment profit		9,035	10,072	25,223	24,548
Interest and other income		$ 330	$ 373	$ 441	$ 529