Dispositions of Real Estate and Discontinued Operations (Details)	12 Months Ended
	Dec. 31, 2015 USD ($) item	Dec. 31, 2014 USD ($) property item	Dec. 31, 2013 USD ($) item	Aug. 29, 2014 USD ($)
Operating income from discontinued operations
Income before impairment losses and gain on sales of real estate, net of income taxes		$ 1,736,000	$ 5,879,000
Impairment losses on real estate			(1,372,000)
Gain on sales of real estate, net of income taxes		28,010,000	69,866,000
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Operating income from discontinued operations
Rental and related revenues		1,810,000	16,649,000
Depreciation and amortization expenses			5,862,000
Operating expenses		54,000	3,929,000
Other expenses, net		20,000	979,000
Income before impairment losses and gain on sales of real estate, net of income taxes		1,736,000	5,879,000
Discontinued Operations, Disposed of by Sale [Member]
Operating income from discontinued operations
Gain on sales of real estate, net of income taxes		$ 28,010,000	$ 69,866,000
Discontinued Operations, Held-for-sale [Member]
Operating income from discontinued operations
Number of properties included in discontinued operations | item		3	16
Senior housing | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Dispositions of Real Estate and Land
Number of properties disposed | item	9	1
Total consideration for disposition of real estate	$ 60,000,000	$ 16,000,000
Post-acute/skilled | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Dispositions of Real Estate and Land
Number of properties disposed | item		2
Total consideration for disposition of real estate		$ 22,000,000
Life science | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Dispositions of Real Estate and Land
Number of Parcels of land | item	2
Total consideration for disposition of real estate	$ 51,000,000
Hospital | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Dispositions of Real Estate and Land
Number of properties disposed | property		1
Total consideration for disposition of real estate		$ 17,000,000
Medical office
Dispositions of Real Estate and Land
Number of properties disposed | item			2
Total consideration for disposition of real estate			$ 6,000,000
Medical office | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Dispositions of Real Estate and Land
Number of properties disposed | item		1
Total consideration for disposition of real estate	$ 400,000	$ 145,000,000
CCRC JV
Dispositions of Real Estate and Land
Carrying value of properties contributed				$ 92,000,000