XML 65 R49.htm IDEA: XBRL DOCUMENT v3.8.0.1
Notes Payable and Unsecured Credit Facilities Schedule of maturities of long-term debt (Details) - USD ($)
$ in Thousands
Mar. 31, 2018
Dec. 31, 2017
Debt Instrument [Line Items]    
Long-term Debt, Maturities, Repayments of Principal, Remainder of Fiscal Year $ 120,227  
Long-term Debt, Maturities, Repayments of Principal in Year Two 33,044  
Long-term Debt, Maturities, Repayments of Principal in Year Three 539,867  
Long-term Debt, Maturities, Repayments of Principal in Year Four 328,351  
Long-term Debt, Maturities, Repayments of Principal in Year Five 582,647  
Long-term Debt, Maturities, Repayments of Principal after Year Five 2,256,274  
Debt Instrument, Unamortized Discount (Premium), Net 20,142  
Long-term Debt 3,840,268 $ 3,594,977
Unsecured Debt [Member]    
Debt Instrument [Line Items]    
Long-term Debt 2,623,209 $ 2,325,656
Scheduled Principal Payments [Member] | Mortgages [Member]    
Debt Instrument [Line Items]    
Long-term Debt, Maturities, Repayments of Principal, Remainder of Fiscal Year 8,001  
Long-term Debt, Maturities, Repayments of Principal in Year Two 9,519  
Long-term Debt, Maturities, Repayments of Principal in Year Three 11,287  
Long-term Debt, Maturities, Repayments of Principal in Year Four 11,600  
Long-term Debt, Maturities, Repayments of Principal in Year Five 11,799  
Long-term Debt, Maturities, Repayments of Principal after Year Five 45,938  
Debt Instrument, Unamortized Discount (Premium), Net 0  
Long-term Debt 98,144  
Mortgage Loan Maturities [Member] | Mortgages [Member]    
Debt Instrument [Line Items]    
Long-term Debt, Maturities, Repayments of Principal, Remainder of Fiscal Year 112,226  
Long-term Debt, Maturities, Repayments of Principal in Year Two 23,525  
Long-term Debt, Maturities, Repayments of Principal in Year Three 78,580  
Long-term Debt, Maturities, Repayments of Principal in Year Four 66,751  
Long-term Debt, Maturities, Repayments of Principal in Year Five 5,848  
Long-term Debt, Maturities, Repayments of Principal after Year Five 260,336  
Debt Instrument, Unamortized Discount (Premium), Net (8,269)  
Long-term Debt 555,535  
Unsecured Maturities [Member] | Unsecured Debt [Member]    
Debt Instrument [Line Items]    
Long-term Debt, Maturities, Repayments of Principal, Remainder of Fiscal Year 0  
Long-term Debt, Maturities, Repayments of Principal in Year Two 0  
Long-term Debt, Maturities, Repayments of Principal in Year Three 450,000  
Long-term Debt, Maturities, Repayments of Principal in Year Four 250,000  
Long-term Debt, Maturities, Repayments of Principal in Year Five 565,000  
Long-term Debt, Maturities, Repayments of Principal after Year Five 1,950,000  
Debt Instrument, Unamortized Discount (Premium), Net 28,411  
Long-term Debt $ 3,186,589