Segment Disclosures (Details 3) (USD $)	Sep. 30, 2012	Dec. 31, 2011	Oct. 05, 2006 CRC	Sep. 30, 2012 Identifiable segment	Dec. 31, 2011 Identifiable segment	Sep. 30, 2012 Senior housing	Dec. 31, 2011 Senior housing	Sep. 30, 2012 Post-acute/skilled nursing	Dec. 31, 2011 Post-acute/skilled nursing	Sep. 30, 2012 Life science	Dec. 31, 2011 Life science	Sep. 30, 2012 Medical office	Dec. 31, 2011 Medical office	Sep. 30, 2012 Hospital	Dec. 31, 2011 Hospital	Sep. 30, 2012 Other non-segment	Dec. 31, 2011 Other non-segment
Reconciliation of assets from segment to consolidated
Gross segment assets				$ 19,200,529,000	$ 18,417,439,000	$ 5,867,914,000	$ 5,792,196,000	$ 6,057,501,000	$ 5,644,472,000	$ 3,928,661,000	$ 3,886,851,000	$ 2,586,231,000	$ 2,336,302,000	$ 760,222,000	$ 757,618,000
Accumulated depreciation and amortization				(1,885,172,000)	(1,649,845,000)
Total assets	18,079,336,000	17,408,475,000		17,315,357,000	16,767,594,000											672,753,000	538,232,000
Assets held for sale, net	91,226,000	102,649,000														91,226,000	102,649,000
Amount paid in merger in excess of the fair value, recorded as goodwill			51,700,000
Goodwill	$ 50,346,000	$ 50,346,000		$ 50,000,000		$ 31,000,000		$ 3,000,000				$ 11,000,000		$ 5,000,000