Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended
	Mar. 22, 2013	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Summary of information for reportable segments
Rental income		$ 296,834	$ 249,995
Resident fees and services		327,324	158,174
Interest income		9,057	8,141
Other income		700	1,686
Revenues		633,915	417,996
Property operating expenses		253,354	128,801
Net Operating Income from Continuing Operations		380,561	289,195
Interest expense		110,289	88,814
Loss (gain) on derivatives, net	2,309	2,309	555
Depreciation and amortization		187,099	120,907
General and administrative		27,179	27,751
Transaction costs		65,980	5,579
Loss (gain) on extinguishment of debt, net		308	0
Provision for loan losses		0	0
Income (loss) from continuing operations before income taxes and income from unconsolidated entities		(11,987)	45,589
Total assets		20,788,972	19,549,109	19,549,109
Percent Of Assets		1.0	1.0
Percent Of Revenues		1.0	1.0
Senior housing - triple net [Member]
Summary of information for reportable segments
Rental income		185,309	161,936
Resident fees and services		0	0
Interest income		5,844	5,877
Other income		209	847
Revenues		191,362	168,660
Property operating expenses		0	0
Net Operating Income from Continuing Operations		191,362	168,660
Interest expense		(6,545)	(589)
Loss (gain) on derivatives, net		0	0
Depreciation and amortization		(56,255)	(49,446)
General and administrative		0	0
Transaction costs		(494)	(1,523)
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		128,068	117,102
Total assets		8,638,136
Senior housing - operating [Member]
Summary of information for reportable segments
Rental income		0	0
Resident fees and services		327,324	158,174
Interest income		757	0
Other income		0	0
Revenues		328,081	158,174
Property operating expenses		(224,503)	(107,243)
Net Operating Income from Continuing Operations		103,578	50,931
Interest expense		(19,070)	(15,835)
Loss (gain) on derivatives, net		(2,309)	(555)
Depreciation and amortization		(89,875)	(39,773)
General and administrative		0	0
Transaction costs		(65,325)	(1,578)
Loss (gain) on extinguishment of debt, net		308	0
Provision for loan losses		0	0
Income (loss) from continuing operations before income taxes and income from unconsolidated entities		(72,693)	(6,810)
Total assets		7,377,227
Medical facilities [Member]
Summary of information for reportable segments
Rental income		111,525	88,059
Resident fees and services		0	0
Interest income		2,456	2,264
Other income		410	604
Revenues		114,391	90,927
Property operating expenses		(28,851)	(21,558)
Net Operating Income from Continuing Operations		85,540	69,369
Interest expense		(9,572)	(8,274)
Loss (gain) on derivatives, net		0	0
Depreciation and amortization		(40,969)	(31,688)
General and administrative		0	0
Transaction costs		(161)	(2,478)
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		34,838	26,929
Total assets		4,569,112
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		81	235
Revenues		81	235
Property operating expenses		0	0
Net Operating Income from Continuing Operations		81	235
Interest expense		(75,102)	(64,116)
Loss (gain) on derivatives, net		0	0
Depreciation and amortization		0	0
General and administrative		(27,179)	(27,751)
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		(102,200)	(91,632)
Total assets		204,497
International [Member]
Summary of information for reportable segments
Revenues		60,544	0
Total assets		1,797,790	856,895
Percent Of Assets		0.086	0.044
Percent Of Revenues		0.096	0.0
United States [Member]
Summary of information for reportable segments
Revenues		573,371	417,996
Total assets		$ 18,991,182	$ 18,692,214
Percent Of Assets		0.914	0.956
Percent Of Revenues		0.904	1.0