Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified		3 Months Ended	9 Months Ended		9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2012 item	Sep. 30, 2012 Senior housing Brookdale Senior Living item	Sep. 30, 2012 Senior housing Brookdale Senior Living item	Dec. 31, 2011 Senior housing Brookdale Senior Living	Sep. 30, 2012 Gross Assets Operators HCR ManorCare	Dec. 31, 2011 Gross Assets Operators HCR ManorCare	Sep. 30, 2012 Gross Assets Operators Brookdale Senior Living	Dec. 31, 2011 Gross Assets Operators Brookdale Senior Living	Sep. 30, 2012 Gross Assets Operators Emeritus Corporation	Dec. 31, 2011 Gross Assets Operators Emeritus Corporation	Sep. 30, 2012 Gross Assets Operators Sunrise Senior Living	Dec. 31, 2011 Gross Assets Operators Sunrise Senior Living	Sep. 30, 2012 Gross Assets Operators Senior housing HCR ManorCare	Dec. 31, 2011 Gross Assets Operators Senior housing HCR ManorCare	Sep. 30, 2012 Gross Assets Operators Senior housing Brookdale Senior Living	Dec. 31, 2011 Gross Assets Operators Senior housing Brookdale Senior Living	Sep. 30, 2012 Gross Assets Operators Senior housing Emeritus Corporation	Dec. 31, 2011 Gross Assets Operators Senior housing Emeritus Corporation	Sep. 30, 2012 Gross Assets Operators Senior housing Sunrise Senior Living	Dec. 31, 2011 Gross Assets Operators Senior housing Sunrise Senior Living	Sep. 30, 2012 Gross Assets Operators Post-acute/skilled nursing HCR ManorCare	Dec. 31, 2011 Gross Assets Operators Post-acute/skilled nursing HCR ManorCare	Sep. 30, 2012 Revenue Operators HCR ManorCare	Sep. 30, 2011 Revenue Operators HCR ManorCare	Sep. 30, 2012 Revenue Operators HCR ManorCare	Sep. 30, 2011 Revenue Operators HCR ManorCare	Sep. 30, 2012 Revenue Operators Brookdale Senior Living	Sep. 30, 2011 Revenue Operators Brookdale Senior Living	Sep. 30, 2012 Revenue Operators Brookdale Senior Living	Sep. 30, 2011 Revenue Operators Brookdale Senior Living	Sep. 30, 2012 Revenue Operators Emeritus Corporation	Sep. 30, 2011 Revenue Operators Emeritus Corporation	Sep. 30, 2012 Revenue Operators Emeritus Corporation	Sep. 30, 2011 Revenue Operators Emeritus Corporation	Sep. 30, 2012 Revenue Operators Sunrise Senior Living	Sep. 30, 2011 Revenue Operators Sunrise Senior Living	Sep. 30, 2012 Revenue Operators Sunrise Senior Living	Sep. 30, 2011 Revenue Operators Sunrise Senior Living	Sep. 30, 2012 Revenue Operators Senior housing HCR ManorCare	Sep. 30, 2011 Revenue Operators Senior housing HCR ManorCare	Sep. 30, 2012 Revenue Operators Senior housing HCR ManorCare	Sep. 30, 2011 Revenue Operators Senior housing HCR ManorCare	Sep. 30, 2012 Revenue Operators Senior housing Brookdale Senior Living	Sep. 30, 2011 Revenue Operators Senior housing Brookdale Senior Living	Sep. 30, 2012 Revenue Operators Senior housing Brookdale Senior Living	Sep. 30, 2011 Revenue Operators Senior housing Brookdale Senior Living	Sep. 30, 2012 Revenue Operators Senior housing Emeritus Corporation	Sep. 30, 2011 Revenue Operators Senior housing Emeritus Corporation	Sep. 30, 2012 Revenue Operators Senior housing Emeritus Corporation	Sep. 30, 2011 Revenue Operators Senior housing Emeritus Corporation	Sep. 30, 2012 Revenue Operators Senior housing Sunrise Senior Living	Sep. 30, 2011 Revenue Operators Senior housing Sunrise Senior Living	Sep. 30, 2012 Revenue Operators Senior housing Sunrise Senior Living	Sep. 30, 2011 Revenue Operators Senior housing Sunrise Senior Living	Sep. 30, 2012 Revenue Operators Post-acute/skilled nursing HCR ManorCare	Sep. 30, 2011 Revenue Operators Post-acute/skilled nursing HCR ManorCare	Sep. 30, 2012 Revenue Operators Post-acute/skilled nursing HCR ManorCare	Sep. 30, 2011 Revenue Operators Post-acute/skilled nursing HCR ManorCare
Concentration of Credit Risk
Concentration risk					34.00%	35.00%	4.00%	5.00%	6.00%	6.00%	7.00%	7.00%	14.00%	14.00%	14.00%	14.00%	18.00%	19.00%	22.00%	22.00%	89.00%	94.00%	30.00%	32.00%	31.00%	22.00%	5.00%	5.00%	5.00%	5.00%	7.00%	7.00%	7.00%	7.00%	5.00%	6.00%	5.00%	6.00%	12.00%	13.00%	12.00%	9.00%	14.00%	16.00%	14.00%	17.00%	20.00%	23.00%	21.00%	25.00%	16.00%	18.00%	16.00%	21.00%	87.00%	93.00%	91.00%	80.00%
Concentration risk, assets		$ 685.4	$ 685.4	$ 682.7
Concentration risk, revenue		$ 36.1	$ 106.8
Number of senior living communities operated in a RIDEA structure	21	21	21
Percentage of operator assets to segment assets after inclusion of assets under RIDEA structure															25.00%	26.00%
Percentage of operator assets to total entity assets after inclusion of assets under RIDEA structure							8.00%	9.00%
Percentage of operator revenue to segment revenue after inclusion of revenue under RIDEA structure																																											38.00%		38.00%
Percentage of operator revenue to total entity revenue after inclusion of revenue under RIDEA structure																											12.00%		12.00%