Segment Disclosures (Details 3) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Reconciliation of assets from segment to consolidated
Total assets	$ 19,732,731	[1]	$ 19,915,555	[1]
Goodwill	50,346		50,346
Identifiable segment
Reconciliation of assets from segment to consolidated
Gross segment assets	21,176,042		21,058,228
Accumulated depreciation and amortization	(2,079,778)		(1,978,597)
Total assets	19,096,264		19,079,631
Senior housing
Reconciliation of assets from segment to consolidated
Gross segment assets	7,739,727		7,658,612
Goodwill	31,000
Post-acute/skilled nursing
Reconciliation of assets from segment to consolidated
Gross segment assets	6,098,982		6,080,826
Goodwill	3,000
Life science
Reconciliation of assets from segment to consolidated
Gross segment assets	3,943,454		3,932,397
Medical office
Reconciliation of assets from segment to consolidated
Gross segment assets	2,664,053		2,661,394
Goodwill	11,000
Hospital
Reconciliation of assets from segment to consolidated
Gross segment assets	729,826		724,999
Goodwill	5,000
Other non-segment assets
Reconciliation of assets from segment to consolidated
Total assets	$ 636,467		$ 835,924

[1] The Company's consolidated total assets at March 31, 2013 and 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 in each period presented; cash and cash equivalents, $10 million in each period presented; and other assets, net, $3 million and $2 million, respectively. See Note 16 to the Condensed Consolidated Financial Statements for additional information.