Debt - Debt Maturities of Mortgages and Notes Payable, Including Balloon Payments (Details) (USD $)
In Thousands, unless otherwise specified
Sep. 30, 2014
Dec. 31, 2013
Scheduled Principal Payments For Borrowings [Line Items]    
Total debt, net $ 4,007,828 $ 3,778,218
Mortgages and Notes Payable
   
Scheduled Principal Payments For Borrowings [Line Items]    
Remainder of 2014 111,952 [1]  
2015 277,565  
2016 439,950  
2017 858,109  
2018 276,135  
Thereafter 2,094,641  
Total debt, net 4,058,352  
Mortgages and Notes Payable | Scheduled Principal
   
Scheduled Principal Payments For Borrowings [Line Items]    
Remainder of 2014 8,202 [1]  
2015 31,783  
2016 30,011  
2017 28,331  
2018 27,284  
Thereafter 96,334  
Total debt, net 221,945  
Mortgages and Notes Payable | Balloon Payment
   
Scheduled Principal Payments For Borrowings [Line Items]    
Remainder of 2014 103,750 [1]  
2015 245,782  
2016 409,939  
2017 829,778  
2018 248,851  
Thereafter 1,998,307  
Total debt, net $ 3,836,407  
[1] The balloon payment balance in 2014 includes $74.0 million for the acceleration of principal payable following an event of default under four separate CMBS loans.