v2.4.0.6
Accounting Policies (Details) (USD $)
1 Months Ended 12 Months Ended 1 Months Ended
Jun. 30, 2010
segment
Dec. 31, 2011
M
tranche
D
segment
Dec. 31, 2010
Dec. 31, 2009
Dec. 31, 2011
Building
Y
Jul. 31, 2010
Lillibridge Acquisition
property
Cash Equivalents            
Maximum term of maturity to classify investments as cash equivalents (in months)   3 months        
Deferred Financing Costs            
Deferred financing costs, net of accumulated amortization   $ 26,669,000 $ 19,533,000      
Amortized costs included in interest expense   17,800,000 17,800,000 14,600,000    
Fair Values of Financial Instruments            
Number of entity shares issued in exchange for redemption of OP Units   0.7866        
Number of foreign currency tranches reported at fair value   2        
Revenue Recognition            
Straight-line rent receivables   $ 96,883,000 $ 86,275,000      
Term of resident lease agreements, minimum (in months)   12        
Term of resident lease agreements, maximum (in months)   18        
Notice period to cancel lease agreements by the resident (in days)   30        
Segment Reporting            
Number of reportable business segments 2 3        
Business acquisition            
Number of Medical office buildings           96
Estimated remaining life (in years)         35