Credit Concentration (Details) (USD $)	6 Months Ended
	Jun. 30, 2014 properties		Dec. 31, 2013
Concentration by investment:
Number of properties in diversified portfolio	1,157
Net real estate investments	$ 21,912,312,000		$ 21,680,221,000
Percent of Investment	100.00%	[1]
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	179	[2]
Net real estate investments	2,681,574,000	[3]
Percent of Investment	12.00%	[1]
Benchmark Senior Living [Member]
Concentration by investment:
Number of properties in diversified portfolio	39	[2]
Net real estate investments	929,443,000	[3]
Percent of Investment	4.00%	[1]
Remaining Portfolio [Member]
Concentration by investment:
Number of properties in diversified portfolio	751	[2]
Net real estate investments	12,308,922,000	[3]
Percent of Investment	57.00%	[1]
Belmont Village [Member]
Concentration by investment:
Number of properties in diversified portfolio	19	[2]
Net real estate investments	832,909,000	[3]
Percent of Investment	4.00%	[1]
Sunrise Senior Living [Member]
Concentration by investment:
Number of properties in diversified portfolio	121	[2]
Net real estate investments	4,001,436,000	[3],[4]
Percent of Investment	18.00%	[1]
Revera [Member]
Concentration by investment:
Number of properties in diversified portfolio	48	[2]
Net real estate investments	$ 1,158,028,000	[3],[4]
Percent of Investment	5.00%	[1]

[1] Investments with our top five relationships comprised 44% of total investments at December 31, 2013

[2] 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

[3] Excludes our share of investments in unconsolidated entities. Please see Note 7 for additional information

[4] Revera owns a controlling interest in Sunrise.