Segment Reporting (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Summary of information for reportable segments
Rental income	$ 336,455,000	$ 292,643,000
Resident fees and services	456,265,000	327,324,000
Interest income	8,594,000	9,057,000
Other income	493,000	700,000
Revenues	801,807,000	629,724,000
Property operating expenses	341,431,000	252,823,000
Net Operating Income from Continuing Operations	460,376	376,901,000
Interest expense	120,833,000	108,838,000
Loss (gain) on derivatives, net	0	2,309,000
Depreciation and amortization	233,318,000	184,688,000
General and administrative	32,865,000	27,179,000
Transaction costs	952,000	65,980,000
Loss (gain) on extinguishment of debt, net	(148,000)	(308,000)
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	72,556,000	(11,785,000)
Total assets	23,211,042,000		23,083,957,000
Percent Of Assets	1	1	1
Percent Of Revenues	1	1
Senior housing - triple net [Member]
Summary of information for reportable segments
Rental income	214,828,000	183,296,000
Resident fees and services	0	0
Interest income	5,439,000	5,844,000
Other income	121,000	209,000
Revenues	220,388,000	189,349,000
Property operating expenses	0	0
Net Operating Income from Continuing Operations	220,388,000	189,349,000
Interest expense	(8,890,000)	(5,805,000)
Loss (gain) on derivatives, net	0	0
Depreciation and amortization	(61,404,000)	(54,950,000)
General and administrative	0	0
Transaction costs	(275,000)	(494,000)
Loss (gain) on extinguishment of debt, net	0	0
Provision for loan losses	0	0
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	149,819,000	128,100,000
Total assets	9,407,112,000
Senior housing - operating [Member]
Summary of information for reportable segments
Rental income	0	0
Resident fees and services	456,265	327,324,000
Interest income	0	757,000
Other income	54	0
Revenues	456,319	328,081,000
Property operating expenses	(308,184)	(224,503,000)
Net Operating Income from Continuing Operations	148,135	103,578,000
Interest expense	(27,479)	(19,070,000)
Loss (gain) on derivatives, net	0	(2,309,000)
Depreciation and amortization	(129,162)	(89,875,000)
General and administrative	0	0
Transaction costs	(630)	(65,325,000)
Loss (gain) on extinguishment of debt, net	148	308,000
Provision for loan losses	0	0
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	(8,988)	(72,693,000)
Total assets	9,081,864,000
Medical facilities [Member]
Summary of information for reportable segments
Rental income	121,627	109,347,000
Resident fees and services	0	0
Interest income	3,155	2,456,000
Other income	303	410,000
Revenues	125,085	112,213,000
Property operating expenses	(33,247)	(28,320,000)
Net Operating Income from Continuing Operations	91,838	83,893,000
Interest expense	(9,608)	(8,861,000)
Loss (gain) on derivatives, net	0	0
Depreciation and amortization	(42,752)	(39,863,000)
General and administrative	0	0
Transaction costs	(47)	(161,000)
Loss (gain) on extinguishment of debt, net	0	0
Provision for loan losses	0	0
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	39,431	35,008,000
Total assets	4,670,775,000
Non Segment Corporate [Member]
Summary of information for reportable segments
Rental income	0	0
Resident fees and services	0	0
Interest income	0	0
Other income	15	81,000
Revenues	15	81,000
Property operating expenses	0	0
Net Operating Income from Continuing Operations	15	81,000
Interest expense	(74,856)	(75,102,000)
Loss (gain) on derivatives, net	0	0
Depreciation and amortization	0	0
General and administrative	(32,865)	(27,179,000)
Transaction costs	0	0
Loss (gain) on extinguishment of debt, net	0	0
Provision for loan losses	0	0
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	(107,706)	(102,200,000)
Total assets	51,291,000
International [Member]
Summary of information for reportable segments
Revenues	126,708,000	60,403,000
Total assets	3,097,702,000	3,324,012,000	3,324,012,000
Percent Of Assets	0.133	0.144	0.144
Percent Of Revenues	0.158	0.096
United States [Member]
Summary of information for reportable segments
Revenues	675,099,000	569,321,000
Total assets	$ 20,113,340,000		$ 19,759,945,000
Percent Of Assets	0.867		0.856
Percent Of Revenues	0.842	0.904