Concentration of Credit Risk (Details) (USD $) In Millions, unless otherwise specified				12 Months Ended				12 Months Ended
	Dec. 31, 2013 state province	Mar. 31, 2013	Dec. 31, 2013 Seniors Housing Communities property	Dec. 31, 2013 Total gross book value of properties Seniors Housing Communities	Dec. 31, 2013 Total gross book value of properties Skilled nursing facilities, hospitals, MOBs and other healthcare assets	Dec. 31, 2013 Total revenues or NOI California	Dec. 31, 2013 ATRIA	Dec. 31, 2013 ATRIA Total gross book value of properties	Dec. 31, 2013 SUNRISE Total gross book value of properties	Dec. 31, 2013 BROOKDALE SENIOR LIVING Total gross book value of properties	Dec. 31, 2013 BROOKDALE SENIOR LIVING Total revenues	Dec. 31, 2012 BROOKDALE SENIOR LIVING Total revenues	Dec. 31, 2011 BROOKDALE SENIOR LIVING Total revenues	Dec. 31, 2013 BROOKDALE SENIOR LIVING Total NOI	Dec. 31, 2012 BROOKDALE SENIOR LIVING Total NOI	Dec. 31, 2011 BROOKDALE SENIOR LIVING Total NOI	Dec. 31, 2013 KINDRED	Dec. 31, 2013 KINDRED Skilled Nursing Facilities	Dec. 31, 2013 KINDRED Long-term Acute Care Hospitals	Dec. 31, 2013 KINDRED Total gross book value of properties	Dec. 31, 2013 KINDRED Total revenues	Dec. 31, 2012 KINDRED Total revenues	Dec. 31, 2011 KINDRED Total revenues	Dec. 31, 2013 KINDRED Total NOI	Dec. 31, 2012 KINDRED Total NOI	Dec. 31, 2011 KINDRED Total NOI
Concentration of credit risk
Percentage of real estate investments based on gross book value (as a percent)				64.20%	35.80%			19.90%	13.90%	9.70%	5.60%	6.30%	7.70%	9.20%	10.50%	12.50%				3.20%	8.10%	10.30%	14.30%	13.40%	17.10%	23.40%
Number of states	46
Number of Canadian provinces	2
Number of states accounting for more than 10% of total revenues						1
Number of 2015 Properties Re-Leased in 2013																	48	26	22
Number of Properties whose Lease Expires in 2015																	108
New Annual Base Rent for the Re-Leased Properties																	$ 95.9
One-time Base Rent Increase in 2014																	15
Fee Received for 2013 Lease Modifications																	$ 20
Number of 2015 Properties Not Re Leased in 2013																	60
Number of seniors housing communities under long-term management agreements			237
Ownership interests in properties accounted for under the equity method (as a percent)		5.00%					34.00%