Segment Reporting (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)		Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Summary of information for reportable segments
Rental income	$ 1,598,948		$ 1,405,767	$ 1,227,589
Resident fees and services	2,158,031		1,892,237	1,616,290
Interest income	84,141		37,667	32,663
Other income	18,706		7,875	4,066
Total revenues	3,859,826		3,343,546	2,880,608
Property operating expenses	1,622,257		1,403,358	1,206,813
Net Operating Income, Total	2,237,569	[1]	1,940,188	1,673,795
Interest expense	492,169		481,039	458,360
Loss (gain) on derivatives, net	(58,427)		(1,495)	4,470
Depreciation and amortization expenses	826,240		844,130	865,800
General and administrative	147,416		142,943	108,318
Transaction costs	110,926		69,538	133,401
Loss (gain) on extinguishment of debt, net	34,677		9,558	(909)
Impairment of Asset	2,220		0	0
Other expenses	46,231		10,262	0
Provision for loan losses	0		0	(2,110)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Cumulative Effects of Changes in Accounting Principles, Noncontrolling Interest, Total	636,117		384,213	102,245
Income tax (expense) benefit	(6,451)		1,267	(7,491)
(Loss) income from unconsolidated entities	(21,504)		(27,426)	(8,187)
Income (loss) from continuing operations	608,162		358,054	86,567
Discontinued operations, net	0		7,135	51,713
Gain (loss) on real estate dispositions, net	280,387		147,111	0
Net income (loss)	888,549		512,300	$ 138,280
Total assets	$ 29,023,845		$ 24,962,923
Segment Reporting (Textuals)
Percent of Assets	1		1
Percent of Revenues	1		1	1
Triple Net [Member]
Summary of information for reportable segments
Rental income	$ 1,119,322		$ 992,638	$ 866,138
Resident fees and services	0		0	0
Interest income	74,108		32,255	28,214
Other income	6,871		2,973	1,504
Total revenues	1,200,301		1,027,866	895,856
Property operating expenses	0		732	1,235
Net Operating Income, Total	1,200,301		1,027,134	894,621
Interest expense	30,288		38,460	23,322
Loss (gain) on derivatives, net	(58,427)		(1,770)	4,877
Depreciation and amortization expenses	294,484		273,296	249,913
General and administrative	0		0	0
Transaction costs	53,254		45,146	24,426
Loss (gain) on extinguishment of debt, net	10,095		98	40
Impairment of Asset	2,220
Other expenses	35,648		8,825
Provision for loan losses	0			(2,110)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Cumulative Effects of Changes in Accounting Principles, Noncontrolling Interest, Total	832,739		663,079	589,933
Income tax (expense) benefit	(4,244)		6,141	(1,817)
(Loss) income from unconsolidated entities	8,260		5,423	5,035
Income (loss) from continuing operations	836,755		674,643	593,151
Discontinued operations, net			7,135	57,742
Gain (loss) on real estate dispositions, net	86,261		146,205
Net income (loss)	923,016		827,983	650,893
Total assets	12,692,054		10,918,946
Senior Housing Operating [Member]
Summary of information for reportable segments
Rental income	0		0	0
Resident fees and services	2,158,031		1,892,237	1,616,290
Interest income	4,180		2,119	757
Other income	6,060		3,215	355
Total revenues	2,168,271		1,897,571	1,617,402
Property operating expenses	1,467,009		1,266,308	1,089,239
Net Operating Income, Total	701,262		631,263	528,163
Interest expense	147,832		113,099	92,148
Loss (gain) on derivatives, net	0		275	(407)
Depreciation and amortization expenses	351,733		418,199	478,007
General and administrative	0		0	0
Transaction costs	54,966		16,880	107,066
Loss (gain) on extinguishment of debt, net	(195)		383	(3,372)
Impairment of Asset	0
Other expenses	0		1,437
Provision for loan losses	0			0
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Cumulative Effects of Changes in Accounting Principles, Noncontrolling Interest, Total	146,926		80,990	(145,279)
Income tax (expense) benefit	986		(3,047)	(5,337)
(Loss) income from unconsolidated entities	(32,672)		(38,204)	(22,695)
Income (loss) from continuing operations	115,240		39,739	(173,311)
Discontinued operations, net			0	0
Gain (loss) on real estate dispositions, net	0		0
Net income (loss)	115,240		39,739	(173,311)
Total assets	11,519,902		9,519,833
Outpatient Medical [Member]
Summary of information for reportable segments
Rental income	479,626		413,129	361,451
Resident fees and services	0		0	0
Interest income	5,853		3,293	3,692
Other income	4,684		1,010	1,911
Total revenues	490,163		417,432	367,054
Property operating expenses	155,248		136,318	116,339
Net Operating Income, Total	334,915		281,114	250,715
Interest expense	28,822		32,904	36,823
Loss (gain) on derivatives, net	0		0	0
Depreciation and amortization expenses	180,023		152,635	137,880
General and administrative	0		0	0
Transaction costs	2,706		7,512	1,909
Loss (gain) on extinguishment of debt, net	0		405	0
Impairment of Asset	0
Other expenses	0		0
Provision for loan losses	0			0
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Cumulative Effects of Changes in Accounting Principles, Noncontrolling Interest, Total	123,364		87,658	74,103
Income tax (expense) benefit	245		(1,827)	(270)
(Loss) income from unconsolidated entities	2,908		5,355	9,473
Income (loss) from continuing operations	126,517		91,186	83,306
Discontinued operations, net			0	(6,029)
Gain (loss) on real estate dispositions, net	194,126		906
Net income (loss)	320,643		92,092	77,277
Total assets	4,727,227		4,464,857
Non Segment Corporate [Member]
Summary of information for reportable segments
Rental income	0		0	0
Resident fees and services	0		0	0
Interest income	0		0	0
Other income	1,091		677	296
Total revenues	1,091		677	296
Property operating expenses	0		0	0
Net Operating Income, Total	1,091		677	296
Interest expense	285,227		296,576	306,067
Loss (gain) on derivatives, net	0		0	0
Depreciation and amortization expenses	0		0	0
General and administrative	147,416		142,943	108,318
Transaction costs	0		0	0
Loss (gain) on extinguishment of debt, net	24,777		8,672	2,423
Impairment of Asset	0
Other expenses	10,583		0
Provision for loan losses	0			0
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Cumulative Effects of Changes in Accounting Principles, Noncontrolling Interest, Total	(466,912)		(447,514)	(416,512)
Income tax (expense) benefit	(3,438)		0	(67)
(Loss) income from unconsolidated entities	0		0	0
Income (loss) from continuing operations	(470,350)		(447,514)	(416,579)
Discontinued operations, net			0	0
Gain (loss) on real estate dispositions, net	0		0
Net income (loss)	(470,350)		(447,514)	(416,579)
Total assets	84,662		59,287
International [Member]
Summary of information for reportable segments
Total revenues	726,499		542,072	$ 391,412
Total assets	$ 3,028,052		$ 5,107,847
Segment Reporting (Textuals)
Percent of Assets	0.104		0.205
Percent of Revenues	0.188		0.162	0.136
United States [Member]
Summary of information for reportable segments
Total revenues	$ 3,133,327		$ 2,801,474	$ 2,489,196
Total assets	$ 25,995,793		$ 19,855,076
Segment Reporting (Textuals)
Percent of Assets	0.896		0.795
Percent of Revenues	0.812		0.838	0.864

[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.