SEGMENT INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 segment	Jun. 30, 2011	Dec. 31, 2011
SEGMENT INFORMATION
Number of reportable business segments			3
Revenues:
Rental income	$ 297,572	$ 139,908	$ 569,209	$ 278,765
Resident fees and services	304,020	201,307	589,815	315,809
Medical office building and other services revenue	6,639	9,822	12,247	16,779
Income from loans and investments	8,152	8,391	16,188	14,476
Interest and other income	65	78	112	156
Total revenues	616,448	359,506	1,187,571	625,985
Less:
Interest and other income	65	78	112	156
Property-level operating expenses	237,394	144,172	453,958	230,959
Medical office building services costs	3,839	7,954	6,827	13,490
Segment NOI	375,150	207,302	726,674	381,380
Income (loss) from unconsolidated entities	514	(83)	831	(253)
Segment profit	375,664	207,219	727,505	381,127
Interest and other income	65	78	112	156
Interest expense	(74,428)	(52,043)	(144,056)	(92,830)
Depreciation and amortization	(189,349)	(79,509)	(351,605)	(130,070)
General, administrative and professional fees	(26,710)	(15,554)	(48,907)	(30,386)
Loss on extinguishment of debt	(9,989)	(6)	(39,533)	(16,526)
Merger-related expenses and deal costs	(36,668)	(55,807)	(44,649)	(62,256)
Other	(1,510)	8,056	(3,086)	8,055
Income tax benefit (expense)	5,179	6,110	(6,159)	9,307
Discontinued operations	31,482	1,190	74,206	2,203
Net income	73,736	19,734	163,828	68,780	363,261
Triple-Net Leased Properties
Revenues:
Rental income	207,898	116,150	415,026	230,771
Medical office building and other services revenue	1,110	0	2,219	0
Total revenues	209,008	116,150	417,245	230,771
Less:
Segment NOI	209,008	116,150	417,245	230,771
Income (loss) from unconsolidated entities	454	0	720	0
Segment profit	209,462	116,150	417,965	230,771
Senior Living Operations
Revenues:
Resident fees and services	304,020	201,307	589,815	315,809
Total revenues	304,020	201,307	589,815	315,809
Less:
Property-level operating expenses	207,548	135,894	403,214	214,005
Segment NOI	96,472	65,413	186,601	101,804
Segment profit	96,472	65,413	186,601	101,804
MOB Operations
Revenues:
Rental income	89,674	23,758	154,183	47,994
Medical office building and other services revenue	5,529	9,822	10,028	16,779
Total revenues	95,203	33,580	164,211	64,773
Less:
Property-level operating expenses	29,846	8,278	50,744	16,954
Medical office building services costs	3,839	7,954	6,827	13,490
Segment NOI	61,518	17,348	106,640	34,329
Income (loss) from unconsolidated entities	60	(83)	111	(253)
Segment profit	61,578	17,265	106,751	34,076
All Other
Revenues:
Income from loans and investments	8,152	8,391	16,188	14,476
Interest and other income	65	78	112	156
Total revenues	8,217	8,469	16,300	14,632
Less:
Interest and other income	65	78	112	156
Segment NOI	8,152	8,391	16,188	14,476
Segment profit	8,152	8,391	16,188	14,476
Interest and other income	$ 65	$ 78	$ 112	$ 156