Credit Concentration (Details) (USD $)	9 Months Ended
	Sep. 30, 2014 properties		Dec. 31, 2013
Concentration by investment:
Number of properties in diversified portfolio	1,180	[1],[2]
Net real estate investments	$ 21,959,272,000	[1],[2]	$ 21,680,221,000
Percent of Investment	100.00%	[1],[3]
Credit Concentration (Textual) [Abstract]
Percentage total investments with top five customers			44.00%
Genesis HealthCare [Member]
Concentration by investment:
Number of properties in diversified portfolio	180	[1],[2]
Net real estate investments	2,670,981,000	[1],[2]
Percent of Investment	12.00%	[1],[3]
Benchmark Senior Living [Member]
Concentration by investment:
Number of properties in diversified portfolio	39	[1],[2]
Net real estate investments	924,285,000	[1],[2]
Percent of Investment	4.00%	[1],[3]
Remaining Portfolio [Member]
Concentration by investment:
Number of properties in diversified portfolio	762	[1],[2]
Net real estate investments	12,310,135,000	[1],[2]
Percent of Investment	56.00%	[1],[3]
Belmont Village [Member]
Concentration by investment:
Number of properties in diversified portfolio	19	[1],[2]
Net real estate investments	826,674,000	[1],[2]
Percent of Investment	4.00%	[1],[3]
Sunrise Senior Living [Member]
Concentration by investment:
Number of properties in diversified portfolio	132	[1],[2],[4]
Net real estate investments	4,142,650,000	[1],[2],[4]
Percent of Investment	19.00%	[1],[3],[4]
Revera [Member]
Concentration by investment:
Number of properties in diversified portfolio	48	[1],[2],[4]
Net real estate investments	$ 1,084,547,000	[1],[2],[4]
Percent of Investment	5.00%	[1],[3],[4]

[1] (1)     Genesis is in our seniors housing triple-net segment. Sunrise, Revera, and Belmont Village are in our seniors housing operating segment. Benchmark is in both our seniors housing triple-net and seniors housing operating segments.

[2] (2)     Excludes our share of investments in unconsolidated entities. Please see Note ##7NOTE for additional information.

[3] (3)     Investments with our top five relationships comprised 44% of total investments at ##D<PYE>.

[4] (4)     Revera owns a controlling interest in Sunrise.