Credit Concentration (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013 properties		Dec. 31, 2012
Concentration by investment:
Number of Properties	1,077	[1]
Total Investment	$ 19,964,116	[1]
Percent of Investment	100.00%	[2]
Credit Concentration (Textual) [Abstract]
Percentage total investments with top five customers			37.00%
Genesis HealthCare [Member]
Concentration by investment:
Number of Properties	176	[1],[3]
Total Investment	2,656,736	[1],[3]
Percent of Investment	13.00%	[2],[3]
Merrill Gardens [Member]
Concentration by investment:
Number of Properties	48	[1]
Total Investment	1,066,129	[1]
Percent of Investment	5.00%	[2]
Remaining Portfolio [Member]
Concentration by investment:
Number of Properties	716	[1]
Total Investment	11,456,459	[1]
Percent of Investment	59.00%	[2]
Belmont Village [Member]
Concentration by investment:
Number of Properties	19	[1]
Total Investment	870,281	[1]
Percent of Investment	4.00%	[2]
Sunrise Senior Living [Member]
Concentration by investment:
Number of Properties	71	[1]
Total Investment	2,694,430	[1]
Percent of Investment	13.00%	[2]
Revera [Member]
Concentration by investment:
Number of Properties	47	[1]
Total Investment	$ 1,220,081	[1]
Percent of Investment	6.00%	[2]

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

[2] Investments with our top five relationships comprised 37% of total investments at December 31, 2012.

[3] Genesis is in our seniors housing triple-net segment whereas the other top five relationships are in our seniors housing operating segment.