Segment Disclosures (Details 3) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Reconciliation of assets from segment to consolidated
Assets held-for-sale, net	$ 6,936	$ 9,578
Total assets	20,051,793	19,915,555	[1]
Goodwill	50,346	50,346
Identifiable segment
Reconciliation of assets from segment to consolidated
Gross segment assets	21,556,805	21,040,674
Accumulated depreciation and amortization	(2,178,621)	(1,970,621)
Assets held-for-sale, net	6,936	9,578
Total assets	19,385,120	19,079,631
Senior housing
Reconciliation of assets from segment to consolidated
Gross segment assets	7,799,169	7,654,221
Goodwill	31,000
Post-acute/skilled nursing
Reconciliation of assets from segment to consolidated
Gross segment assets	6,389,017	6,080,826
Goodwill	3,000
Life science
Reconciliation of assets from segment to consolidated
Gross segment assets	3,955,373	3,932,397
Medical office
Reconciliation of assets from segment to consolidated
Gross segment assets	2,679,908	2,661,394
Goodwill	11,000
Hospital
Reconciliation of assets from segment to consolidated
Gross segment assets	733,338	711,836
Assets held-for-sale, net	7,000
Goodwill	5,000
Other non-segment assets
Reconciliation of assets from segment to consolidated
Total assets	$ 666,673	$ 835,924

[1] The Company's consolidated total assets at December 31, 2012, include assets of certain variable interest entities ("VIEs") that can only be used to settle the liabilities of those VIEs as follows: accounts receivable, net, $2 million; cash and cash equivalents, $10 million; and other assets, net, $2 million. See Note 16 to the Condensed Consolidated Financial Statements for additional information.