Credit Concentration (Details) $ in Thousands		3 Months Ended
		Mar. 31, 2017 USD ($) properties	Mar. 31, 2016 USD ($)	Dec. 31, 2016
Concentration by investment:
Number of properties in diversified portfolio | properties	[1]	1,277
Percent of NOI	[1],[2]	100.00%
Net Operating Income | $		$ 552,129	$ 597,414
Credit Concentration (Textual) [Abstract]
Percentage total investments with top five customers				45.00%
Genesis HealthCare [Member]
Concentration by investment:
Number of properties in diversified portfolio | properties	[1]	86
Genesis HealthCare [Member] | Net Operating Income [Member]
Concentration by investment:
Percent of NOI	[1],[2]	9.00%
Net Operating Income | $	[1]	$ 49,048
Sunrise Senior Living [Member]
Concentration by investment:
Number of properties in diversified portfolio | properties	[1],[3]	153
Sunrise Senior Living [Member] | Net Operating Income [Member]
Concentration by investment:
Percent of NOI	[1],[2],[3]	14.00%
Net Operating Income | $	[1],[3]	$ 74,893
Brookdale [Member]
Concentration by investment:
Number of properties in diversified portfolio | properties	[1]	137
Brookdale [Member] | Net Operating Income [Member]
Concentration by investment:
Percent of NOI	[1],[2]	7.00%
Net Operating Income | $	[1]	$ 38,372
Revera [Member]
Concentration by investment:
Number of properties in diversified portfolio | properties	[1],[3]	98
Revera [Member] | Net Operating Income [Member]
Concentration by investment:
Percent of NOI	[1],[2],[3]	7.00%
Net Operating Income | $	[1],[3]	$ 37,802
Benchmark Senior Living [Member]
Concentration by investment:
Number of properties in diversified portfolio | properties	[1]	48
Benchmark Senior Living [Member] | Net Operating Income [Member]
Concentration by investment:
Percent of NOI	[1],[2]	4.00%
Net Operating Income | $	[1]	$ 22,614
Remaining Portfolio [Member]
Concentration by investment:
Number of properties in diversified portfolio | properties	[1]	755
Remaining Portfolio [Member] | Net Operating Income [Member]
Concentration by investment:
Percent of NOI	[1],[2]	59.00%
Net Operating Income | $	[1]	$ 329,400

[1] Genesis Healthcare is in our triple-net segment. Sunrise Senior Living and Revera are in our seniors housing operating segment. Benchmark Senior Living and Brookdale Senior Living are in both our triple-net and seniors housing operating segments.

[2] NOICO with our top five relationships comprised 45% of total NOICO for the year ending December 31, 2016.

[3] Revera owns a controlling interest in Sunrise Senior Living.