Segment Reporting (Details)	3 Months Ended			9 Months Ended
	Sep. 30, 2015 USD ($)		Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)		Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Summary of information for reportable segments
Rental income	$ 409,290,000		$ 354,148,000	$ 1,185,502,000		$ 1,038,451,000
Resident fees and services	545,255,000		482,412,000	1,573,318,000		1,406,316,000
Interest income	22,380,000		9,344,000	59,950,000		26,871,000
Other income	2,072,000		1,619,000	11,572,000		4,139,000
Total revenues	978,997,000		847,523,000	2,830,342,000		2,475,777,000
Property operating expenses	408,703,000		355,157,000	1,183,519,000		1,040,342,000
Net Operating Income from Continuing Operations	570,294,000	[1]	492,366,000	1,646,823,000		1,435,435,000
Interest expense	121,130,000		118,435,000	361,071,000		360,334,000
Loss (gain) on derivatives, net	0		49,000	(58,427,000)	[2]	400,000
Depreciation and amortization	205,799,000		200,970,000	603,431,000		648,737,000
General and administrative	36,950,000		30,803,000	110,562,000		115,327,000
Transaction costs	9,333,000		13,554,000	70,379,000		21,546,000
Loss (gain) on extinguishment of debt, net	584,000		2,692,000	34,872,000		3,075,000
Impairment of Asset	0		0	2,220,000		0
Other expenses	0		10,262,000	10,583,000		10,262,000
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	196,498,000		115,601,000	512,132,000		275,754,000
Income tax (expense) benefit	3,344,000		10,198,000	(3,769,000)		6,369,000
(Loss) income from unconsolidated entities	(2,631,000)		(2,632,000)	(18,231,000)		(19,705,000)
Income (loss) from continuing operations	197,211,000		123,167,000	490,132,000		262,418,000
Discontinued operations, net	0		0	0		7,135,000
Gain (loss) on real estate dispositions, net	2,046,000		29,604,000	249,002,000		36,272,000
Net income	199,257,000		$ 152,771,000	739,134,000		$ 305,825,000
Total assets	$ 27,456,366,000			$ 27,456,366,000			$ 25,014,296,000
Percent Of Assets	1			1
Percent Of Revenues	1		1	1		1
Triple Net [Member]
Summary of information for reportable segments
Rental income	$ 285,027,000		$ 250,748,000	$ 829,422,000		$ 736,599,000
Resident fees and services	0		0	0		0
Interest income	19,454,000		7,520,000	52,343,000		23,220,000
Other income	969,000		981,000	5,823,000		1,448,000
Total revenues	305,450,000		259,249,000	887,588,000		761,267,000
Property operating expenses	0		41,000	0		732,000
Net Operating Income from Continuing Operations	305,450,000		259,208,000	887,588,000		760,535,000
Interest expense	12,359,000		10,294,000	25,064,000		28,063,000
Loss (gain) on derivatives, net	0		52,000	(58,427,000)		125,000
Depreciation and amortization	74,486,000		68,027,000	216,921,000		202,668,000
General and administrative	0		0	0		0
Transaction costs	1,865,000		1,619,000	45,615,000		5,900,000
Loss (gain) on extinguishment of debt, net	(139,000)		(36,000)	10,096,000		(36,000)
Impairment of Asset	0			2,220,000
Other expenses	0		8,825,000	0		8,825,000
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	216,879,000		170,427,000	646,099,000		514,990,000
Income tax (expense) benefit	87,000		5,986,000	(2,617,000)		5,194,000
(Loss) income from unconsolidated entities	2,851,000		1,353,000	5,697,000		4,157,000
Income (loss) from continuing operations	219,817,000		177,766,000	649,179,000		524,341,000
Discontinued operations, net			0			7,135,000
Gain (loss) on real estate dispositions, net	2,155,000		29,604,000	56,251,000		35,366,000
Net income	221,972,000		207,370,000	705,430,000		566,842,000
Total assets	12,346,157,000			12,346,157,000
Senior housing - operating [Member]
Summary of information for reportable segments
Rental income	0		0	0		0
Resident fees and services	545,255,000		482,412,000	1,573,318,000		1,406,316,000
Interest income	1,054,000		1,054,000	3,126,000		1,065,000
Other income	772,000		325,000	5,001,000		1,643,000
Total revenues	547,081,000		483,791,000	1,581,445,000		1,409,024,000
Property operating expenses	368,050,000		320,895,000	1,067,127,000		939,108,000
Net Operating Income from Continuing Operations	179,031,000		162,896,000	514,318,000		469,916,000
Interest expense	30,990,000		26,612,000	104,245,000		82,924,000
Loss (gain) on derivatives, net	0		(3,000)	0		275,000
Depreciation and amortization	87,306,000		95,819,000	252,785,000		334,625,000
General and administrative	0		0	0		0
Transaction costs	7,630,000		10,572,000	23,610,000		12,863,000
Loss (gain) on extinguishment of debt, net	0		0	0		383,000
Impairment of Asset	0			0
Other expenses	0		1,437,000	0		1,437,000
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	53,105,000		28,459,000	133,678,000		37,409,000
Income tax (expense) benefit	3,237,000		3,746,000	(745,000)		1,302,000
(Loss) income from unconsolidated entities	(5,629,000)		(5,550,000)	(26,785,000)		(29,007,000)
Income (loss) from continuing operations	50,713,000		26,655,000	106,148,000		9,704,000
Discontinued operations, net			0			0
Gain (loss) on real estate dispositions, net	0		0	0		0
Net income	50,713,000		26,655,000	106,148,000		9,704,000
Total assets	10,325,540,000			10,325,540,000
Outpatient Medical [Member]
Summary of information for reportable segments
Rental income	124,263,000		103,400,000	356,080,000		301,852,000
Resident fees and services	0		0	0		0
Interest income	1,872,000		770,000	4,481,000		2,586,000
Other income	309,000		207,000	665,000		850,000
Total revenues	126,444,000		104,377,000	361,226,000		305,288,000
Property operating expenses	40,653,000		34,221,000	116,392,000		100,502,000
Net Operating Income from Continuing Operations	85,791,000		70,156,000	244,834,000		204,786,000
Interest expense	7,120,000		7,692,000	21,929,000		25,423,000
Loss (gain) on derivatives, net	0		0	0		0
Depreciation and amortization	44,007,000		37,124,000	133,725,000		111,444,000
General and administrative	0		0	0		0
Transaction costs	(162,000)		1,363,000	1,154,000		2,783,000
Loss (gain) on extinguishment of debt, net	0		0	0		0
Impairment of Asset	0			0
Other expenses	0			0
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	34,826,000		23,977,000	88,026,000		65,136,000
Income tax (expense) benefit	154,000		466,000	460,000		(127,000)
(Loss) income from unconsolidated entities	147,000		1,565,000	2,857,000		5,145,000
Income (loss) from continuing operations	35,127,000		26,008,000	91,343,000		70,154,000
Discontinued operations, net			0			0
Gain (loss) on real estate dispositions, net	(109,000)		0	192,751,000		906,000
Net income	35,018,000		26,008,000	284,094,000		71,060,000
Total assets	4,699,643,000			4,699,643,000
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	22,000		106,000	83,000		198,000
Total revenues	22,000		106,000	83,000		198,000
Property operating expenses	0		0	0		0
Net Operating Income from Continuing Operations	22,000		106,000	83,000		198,000
Interest expense	70,661,000		73,837,000	209,833,000		223,924,000
Loss (gain) on derivatives, net	0		0	0		0
Depreciation and amortization	0		0	0		0
General and administrative	36,950,000		30,803,000	110,562,000		115,327,000
Transaction costs	0		0	0		0
Loss (gain) on extinguishment of debt, net	723,000		2,728,000	24,776,000		2,728,000
Impairment of Asset	0			0
Other expenses	0	[3]		10,583,000
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	(108,312,000)		(107,262,000)	(355,671,000)		(341,781,000)
Income tax (expense) benefit	(134,000)		0	(867,000)		0
(Loss) income from unconsolidated entities	0		0	0		0
Income (loss) from continuing operations	(108,446,000)		(107,262,000)	(356,538,000)		(341,781,000)
Discontinued operations, net			0			0
Gain (loss) on real estate dispositions, net	0		0	0		0
Net income	(108,446,000)		(107,262,000)	(356,538,000)		(341,781,000)
Total assets	85,026,000			85,026,000
International [Member]
Summary of information for reportable segments
Total revenues	185,568,000		$ 139,681,000	520,746,000		$ 396,914,000
Total assets	$ 4,948,132,000			$ 4,948,132,000			$ 4,285,819,000
Percent Of Assets	0.18			0.18			0.171
Percent Of Revenues	0.19		0.165	0.184		0.16
United States [Member]
Summary of information for reportable segments
Total revenues	$ 793,429,000		$ 707,842,000	$ 2,309,596,000		$ 2,078,863,000
Total assets	$ 22,508,234,000			$ 22,508,234,000			$ 20,728,477,000
Percent Of Assets	0.82			0.82			0.829
Percent Of Revenues	0.81		0.835	0.816		0.84

[1] (1)     Genesis Healthcare is in our triple-net segment. Sunrise Senior Living and Revera are in our seniors housing operating segment. Brookdale Senior Living and Benchmark Senior Living are in both our triple-net and seniors housing operating segments.

[2] (1) In April 2011, we completed the acquisition of substantially all of the real estate assets of privately-owned Genesis Healthcare Corporation. In conjunction with this transaction, we received the option to acquire an ownership interest in Genesis Healthcare. In February 2015, Genesis Healthcare closed on a transaction to merge with Skilled Healthcare Group to become a publicly traded company which required us to record the value of the derivative asset due to the net settlement feature.

[3]