Segment Reporting (Details) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2016 USD ($)		Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($)		Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Summary of information for reportable segments
Rental income	$ 422,628		$ 396,626	$ 838,290		$ 776,213
Resident fees and services	615,220		535,553	1,217,369		1,028,063
Interest income	24,007		20,576	49,195		37,570
Other income	14,802		4,414	18,851		9,500
Total revenues	1,076,657		957,169	2,123,705		1,851,346
Property operating expenses	458,832		398,354	908,468		774,815
Net Operating Income from Continuing Operations	617,825	[1]	558,815	1,215,237	[1]	1,076,531
Interest expense	132,326		118,861	265,285		239,942
Loss (gain) on derivatives, net	0		0	0	[2]	(58,427)
Depreciation and amortization	226,569		208,802	455,265		397,631
General and administrative	39,914		38,474	85,606		73,612
Transaction costs	5,157		12,491	13,365		61,045
Loss (gain) on extinguishment of debt, net	33		18,887	9		34,288
Impairment of Asset	0		0	14,314		2,220
Other expenses	3,161		10,583	3,161		10,583
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	210,665		150,717	378,232		315,637
Income tax (expense) benefit	513		(7,417)	2,239		(7,113)
(Loss) income from unconsolidated entities	(1,959)		(2,952)	(5,778)		(15,600)
Income (loss) from continuing operations	209,219		140,348	374,693		292,924
Gain (loss) on real estate dispositions, net	1,530		190,111	1,530		246,956
Net income	210,749		$ 330,459	376,223		$ 539,880
Total assets	$ 28,964,501			$ 28,964,501			$ 29,023,845
Percent Of Assets	1			1			1
Percent Of Revenues	1		1	1		1
Triple Net [Member]
Summary of information for reportable segments
Rental income	$ 287,134		$ 272,573	$ 570,958		$ 534,565
Resident fees and services	0		0	0		0
Interest income	21,971		18,189	44,824		32,888
Other income	1,206		970	2,695		4,853
Total revenues	310,311		291,732	618,477		572,306
Property operating expenses	0		0	0		0
Net Operating Income from Continuing Operations	310,311		291,732	618,477		572,306
Interest expense	2,019		1,313	7,623		9,736
Loss (gain) on derivatives, net	0		0	0		(58,427)
Depreciation and amortization	75,809		70,525	155,609		139,946
General and administrative	0		0	0		0
Transaction costs	1,291		7,579	4,143		43,750
Loss (gain) on extinguishment of debt, net	121		(102)	97		10,235
Impairment of Asset	0		0	14,314		2,220
Other expenses	0		0	0		0
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	231,071		212,417	436,691		424,846
Income tax (expense) benefit	(213)		(3,121)	(528)		(2,703)
(Loss) income from unconsolidated entities	3,018		1,453	6,100		2,846
Income (loss) from continuing operations	233,876		210,749	442,263		424,989
Gain (loss) on real estate dispositions, net	1,530		0	1,530		54,097
Net income	235,406		210,749	443,793		479,086
Total assets	12,201,470			12,201,470
Senior housing - operating [Member]
Summary of information for reportable segments
Rental income	0		0	0		0
Resident fees and services	615,220		535,553	1,217,369		1,028,063
Interest income	1,042		1,042	2,073		2,073
Other income	8,989		3,210	11,178		4,229
Total revenues	625,251		539,805	1,230,620		1,034,365
Property operating expenses	417,996		360,569	826,890		699,076
Net Operating Income from Continuing Operations	207,255		179,236	403,730		335,289
Interest expense	42,689		38,834	83,518		73,293
Loss (gain) on derivatives, net	0		0	0		0
Depreciation and amortization	102,312		88,844	204,144		165,479
General and administrative	0		0	0		0
Transaction costs	3,247		3,937	7,180		15,979
Loss (gain) on extinguishment of debt, net	(88)		0	(88)		0
Impairment of Asset	0		0	0		0
Other expenses	0		0	0		0
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	59,095		47,621	108,976		80,538
Income tax (expense) benefit	2,023		(3,449)	4,789		(3,982)
(Loss) income from unconsolidated entities	(4,887)		(6,083)	(11,822)		(21,156)
Income (loss) from continuing operations	56,231		38,089	101,943		55,400
Gain (loss) on real estate dispositions, net	0		0	0		0
Net income	56,231		38,089	101,943		55,400
Total assets	11,626,090			11,626,090
Outpatient Medical [Member]
Summary of information for reportable segments
Rental income	135,494		124,053	267,332		241,648
Resident fees and services	0		0	0		0
Interest income	994		1,345	2,298		2,609
Other income	4,153		195	4,466		356
Total revenues	140,641		125,593	274,096		244,613
Property operating expenses	40,836		37,785	81,578		75,739
Net Operating Income from Continuing Operations	99,805		87,808	192,518		168,874
Interest expense	5,402		6,993	11,146		14,382
Loss (gain) on derivatives, net	0		0	0		0
Depreciation and amortization	48,448		49,433	95,512		92,206
General and administrative	0		0	0		0
Transaction costs	619		975	2,042		1,316
Loss (gain) on extinguishment of debt, net	0		0	0		0
Impairment of Asset	0		0	0		0
Other expenses	0		0	0		0
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	45,336		30,407	83,818		60,970
Income tax (expense) benefit	(248)		(161)	(476)		305
(Loss) income from unconsolidated entities	(90)		1,678	(56)		2,710
Income (loss) from continuing operations	44,998		31,924	83,286		63,985
Gain (loss) on real estate dispositions, net	0		190,111	0		192,859
Net income	44,998		222,035	83,286		256,844
Total assets	5,020,102			5,020,102
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	454		39	512		62
Total revenues	454		39	512		62
Property operating expenses	0		0	0		0
Net Operating Income from Continuing Operations	454		39	512		62
Interest expense	82,216		71,721	162,998		142,531
Loss (gain) on derivatives, net	0		0	0		0
Depreciation and amortization	0		0	0		0
General and administrative	39,914		38,474	85,606		73,612
Transaction costs	0		0	0		0
Loss (gain) on extinguishment of debt, net	0		18,989	0		24,053
Impairment of Asset	0		0	0		0
Other expenses	3,161		10,583	3,161		10,583
Income (loss) from continuing operations before income taxes and income from unconsolidated entities	(124,837)		(139,728)	(251,253)		(250,717)
Income tax (expense) benefit	(1,049)		(686)	(1,546)		(733)
(Loss) income from unconsolidated entities	0		0	0		0
Income (loss) from continuing operations	(125,886)		(140,414)	(252,799)		(251,450)
Gain (loss) on real estate dispositions, net	0		0	0		0
Net income	(125,886)		(140,414)	(252,799)		(251,450)
Total assets	116,839			116,839
Canada [Member]
Summary of information for reportable segments
Total revenues	111,949		$ 82,607	216,087		$ 139,833
Total assets	$ 2,628,887			$ 2,628,887			$ 1,286,079
Percent Of Assets	0.091			0.091			0.044
Percent Of Revenues	0.104		0.086	0.102		0.076
United Kingdom [Member]
Summary of information for reportable segments
Total revenues	$ 102,593		$ 103,531	$ 203,148		$ 195,345
Total assets	$ 2,789,104			$ 2,789,104			$ 1,741,973
Percent Of Assets	0.096			0.096			0.06
Percent Of Revenues	0.095		0.108	0.095		0.106
United States [Member]
Summary of information for reportable segments
Total revenues	$ 862,115		$ 771,031	$ 1,704,470		$ 1,516,168
Total assets	$ 23,546,510			$ 23,546,510			$ 25,995,793
Percent Of Assets	0.813			0.813			0.896
Percent Of Revenues	0.801		0.806	0.803		0.819

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