XML 66 R44.htm IDEA: XBRL DOCUMENT v3.6.0.2
Significant Accounting Policies (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Accounting Policies [Abstract]      
Period in which the company capitalizes interest, real estate taxes and certain operating expenses on the unoccupied portion of recently completed properties, beginning with the date it is substantially complete (percent) 90.00%    
Period in which the company capitalizes interest, real estate taxes and certain operating expenses on the unoccupied portion of recently completed properties, beginning with the date it is substantially complete (in years) 1 year    
Property, Plant and Equipment [Line Items]      
Reimbursement of rental revenue from tenants $ 90.2 $ 93.3 $ 86.0
Buildings | Minimum      
Property, Plant and Equipment [Line Items]      
Useful life 24 years    
Buildings | Maximum      
Property, Plant and Equipment [Line Items]      
Useful life 42 years    
Furniture, Fixtures and Equipment | Minimum      
Property, Plant and Equipment [Line Items]      
Useful life 3 years    
Furniture, Fixtures and Equipment | Maximum      
Property, Plant and Equipment [Line Items]      
Useful life 5 years