v2.4.0.6
Segment Information (Details 2) (USD $)
12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Assets      
Total assets $ 17,271,910,000 $ 5,758,021,000  
Percentage of total assets 100.00% 100.00%  
Capital expenditures      
Total capital expenditures 629,669,000 294,296,000 127,828,000
Triple-Net Leased Properties
     
Assets      
Total assets 8,704,061,000 2,474,612,000  
Percentage of total assets 50.40% 43.00%  
Capital expenditures      
Total capital expenditures 133,761,000 12,884,000 10,867,000
Capital expenditures from funds held in Code Section 1031 exchange escrow account     9,300,000
Senior Living Operations
     
Assets      
Total assets 5,758,497,000 2,297,041,000  
Percentage of total assets 33.30% 39.90%  
Capital expenditures      
Total capital expenditures 370,455,000 10,268,000 11,081,000
MOB Operations
     
Assets      
Total assets 2,433,160,000 748,945,000  
Percentage of total assets 14.10% 13.00%  
Capital expenditures      
Total capital expenditures 125,453,000 271,144,000 105,880,000
Capital expenditures from funds held in Code Section 1031 exchange escrow account     55,700,000
All Other
     
Assets      
Total assets $ 376,192,000 $ 237,423,000  
Percentage of total assets 2.20% 4.10%