Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended		4 Months Ended	6 Months Ended
	Mar. 22, 2013	Jun. 30, 2013	Jun. 30, 2012	May 03, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Summary of information for reportable segments
Rental income		$ 302,465	$ 263,704		$ 598,753	$ 512,662
Resident fees and services		370,995	165,654		698,319	323,828
Interest income		7,640	7,879		16,696	16,020
Other income		1,025	1,482		1,725	3,166
Revenues		682,125	438,719		1,315,493	855,676
Property operating expenses		278,587	135,839		531,941	264,641
Net Operating Income from Continuing Operations		403,538	302,880		783,552	591,035
Interest expense		110,629	91,299		220,585	179,780
Loss (gain) on derivatives, net	(2,309)	(2,716)	(2,676)	2,772	(407)	(2,121)
Depreciation and amortization		200,108	127,599		386,837	248,136
General and administrative		23,902	25,870		51,081	53,621
Transaction costs		28,136	28,691		94,116	34,270
Loss (gain) on extinguishment of debt, net		0	(576)		308	(576)
Provision for loan losses					0	0
Income (loss) from continuing operations before income taxes and income from unconsolidated entities		43,479	31,521		31,648	76,773
Total assets		22,196,393			22,196,393		19,549,109
Percent Of Assets		1.0			1.0		1.0
Percent Of Revenues		1.0	1.0		1.0	1.0
Senior housing - triple net [Member]
Summary of information for reportable segments
Rental income		188,941	168,911		373,703	329,810
Resident fees and services		0	0		0	0
Interest income		5,433	5,984		11,276	11,861
Other income		199	761		408	1,606
Revenues		194,573	175,656		385,387	343,277
Property operating expenses		0	0		0	0
Net Operating Income from Continuing Operations		194,573	175,656		385,387	343,277
Interest expense		(3,661)	0		(9,873)	(252)
Loss (gain) on derivatives, net		0	(96)		0	(96)
Depreciation and amortization		(55,571)	(52,416)		(111,456)	(101,492)
General and administrative		0	0		0	0
Transaction costs		(11,211)	(23,683)		(11,705)	(25,205)
Loss (gain) on extinguishment of debt, net		0	(2,238)		0	(2,238)
Provision for loan losses		0	0		0	0
Income (loss) from continuing operations before income taxes and income from unconsolidated entities		124,130	97,223		252,353	213,994
Total assets		8,527,476			8,527,476
Senior housing - operating [Member]
Summary of information for reportable segments
Rental income		0	0		0	0
Resident fees and services		370,995	165,654		698,319	323,828
Interest income		0	0		757	0
Other income		0	0		0	0
Revenues		370,995	165,654		699,076	323,828
Property operating expenses		(248,972)	(111,340)		(473,475)	(218,583)
Net Operating Income from Continuing Operations		122,023	54,314		225,601	105,245
Interest expense		(19,412)	(16,227)		(38,482)	(32,062)
Loss (gain) on derivatives, net		2,716	2,772		407	2,217
Depreciation and amortization		(103,646)	(37,745)		(193,521)	(77,518)
General and administrative		0	0		0	0
Transaction costs		(16,799)	(2,821)		(82,124)	(4,399)
Loss (gain) on extinguishment of debt, net		0	1,179		308	1,179
Provision for loan losses		0	0		0	0
Income (loss) from continuing operations before income taxes and income from unconsolidated entities		(15,118)	1,472		(87,811)	(5,338)
Total assets		8,647,125			8,647,125
Medical facilities [Member]
Summary of information for reportable segments
Rental income		113,524	94,793		225,050	182,852
Resident fees and services		0	0		0	0
Interest income		2,207	1,895		4,663	4,159
Other income		662	478		1,072	1,082
Revenues		116,393	97,166		230,785	188,093
Property operating expenses		(29,615)	(24,499)		(58,466)	(46,058)
Net Operating Income from Continuing Operations		86,778	72,667		172,319	142,035
Interest expense		(10,256)	(6,596)		(19,828)	(14,871)
Loss (gain) on derivatives, net		0	0		0	0
Depreciation and amortization		(40,891)	(37,438)		(81,860)	(69,126)
General and administrative		0	0		0	0
Transaction costs		(126)	(2,187)		(287)	(4,666)
Loss (gain) on extinguishment of debt, net		0	483		0	483
Provision for loan losses		0	0		0	0
Income (loss) from continuing operations before income taxes and income from unconsolidated entities		35,505	26,929		70,344	53,855
Total assets		4,544,110			4,544,110
Non Segment Corporate [Member]
Summary of information for reportable segments
Rental income		0	0		0	0
Resident fees and services		0	0		0	0
Interest income		0	0		0	0
Other income		164	243		245	478
Revenues		164	243		245	478
Property operating expenses		0	0		0	0
Net Operating Income from Continuing Operations		164	243		245	478
Interest expense		(77,300)	(68,476)		(152,402)	(132,595)
Loss (gain) on derivatives, net		0	0		0	0
Depreciation and amortization		0	0		0	0
General and administrative		(23,902)	(25,870)		(51,081)	(53,621)
Transaction costs		0	0		0	0
Loss (gain) on extinguishment of debt, net		0	0		0	0
Provision for loan losses		0	0		0	0
Income (loss) from continuing operations before income taxes and income from unconsolidated entities		(101,038)	(94,103)		(203,238)	(185,738)
Total assets		477,682			477,682
International [Member]
Summary of information for reportable segments
Revenues		87,024	2,055		147,568	2,055
Total assets		3,137,237			3,137,237		856,895
Percent Of Assets		0.141			0.141		0.044
Percent Of Revenues		0.128	0.005		0.112	0.002
United States [Member]
Summary of information for reportable segments
Revenues		595,101	436,664		1,167,925	853,621
Total assets		$ 19,059,156			$ 19,059,156		$ 18,692,214
Percent Of Assets		0.859			0.859		0.956
Percent Of Revenues		0.872	0.995		0.888	0.998