Customer Concentration (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Sep. 30, 2012 properties		Dec. 31, 2011
Concentration by investment:
Number of Properties	978	[1]
Total Investment	$ 15,785,857	[1]
Percent of Investment	100.00%	[2],[3]
Customer Concentration (Textual) [Abstract]
Percentage total investments with top five customers			41.00%
Genesis Health Care Corporation [Member]
Concentration by investment:
Number of Properties	158	[1]
Total Investment	2,558,276	[1]
Percent of Investment	16.00%	[2],[3]
Benchmark Senior Living [Member]
Concentration by investment:
Number of Properties	35	[1]
Total Investment	849,397	[1]
Percent of Investment	5.00%	[2],[3]
Merrill Gardens LLC [Member]
Concentration by investment:
Number of Properties	48	[1]
Total Investment	1,095,029	[1]
Percent of Investment	7.00%	[2],[3]
Brandywine Senior Living LLC [Member]
Concentration by investment:
Number of Properties	26	[1]
Total Investment	722,623	[1]
Percent of Investment	5.00%	[2],[3]
Senior Living Communities, LLC [Member]
Concentration by investment:
Number of Properties	12	[1]
Total Investment	607,208	[1]
Percent of Investment	4.00%	[2],[3]
Remaining Portfolio [Member]
Concentration by investment:
Number of Properties	699	[1]
Total Investment	$ 9,953,324	[1]
Percent of Investment	63.00%	[2],[3]

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

[2] Merrill Gardens and Benchmark are in our seniors housing operating segment whereas the other top five customers are in our seniors housing triple-net segment.

[3] Investments with our top five customers comprised 41% of total investments at December 31, 2011.