Segment Disclosures - Assets (Details) - USD ($) $ in Thousands		Jun. 30, 2015	Dec. 31, 2014
Segment Disclosure
Total assets	[1]	$ 22,348,127	$ 21,369,940
Goodwill		50,346	50,346
Operating segment
Segment Disclosure
Gross assets		24,192,970	23,042,397
Accumulated depreciation and amortization		(2,778,924)	(2,600,072)
Total assets		21,414,046	20,442,325
Operating segment | Senior housing
Segment Disclosure
Gross assets		9,449,641	8,383,345
Goodwill		31,000
Operating segment | Post-acute/skilled
Segment Disclosure
Gross assets		6,511,511	6,875,122
Goodwill		3,000
Operating segment | Life science
Segment Disclosure
Gross assets		4,187,616	4,154,789
Operating segment | Medical office
Segment Disclosure
Gross assets		3,404,395	2,988,888
Goodwill		11,000
Operating segment | Hospital
Segment Disclosure
Gross assets		639,807	640,253
Goodwill		5,000
Other non-segment
Segment Disclosure
Total assets		$ 934,081	$ 927,615

[1] The Company’s consolidated total assets at June 30, 2015 and December 31, 2014 include assets of certain variable interest entities (“VIEs”) that can only be used to settle the liabilities of those VIEs. Total assets at June 30, 2015 include VIE assets as follows: buildings and improvements $751 million; land $125 million; accumulated depreciation and amortization $121 million; accounts receivable $16 million; cash $57 million; and other assets, net $24 million. Total assets at December 31, 2014 include VIE assets as follows: buildings and improvements $677 million; land $113 million; accumulated depreciation and amortization $111 million; accounts receivable $5 million; cash $42 million; and other assets, net of $23 million from VIEs. See Note 18 to the Consolidated Financial Statements for additional information.