Annual report pursuant to Section 13 and 15(d)

Debt, Net (Details)

v3.10.0.1
Debt, Net (Details) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Debt    
Carrying Value $ 1,823,909,000 $ 1,828,333,000
Revolving Credit Facility [Member]    
Debt    
Carrying Value $ 213,000,000 126,000,000
Weighted average interest rate (as a percent) 3.49%  
Term Loan Facilities [Member]    
Debt    
Carrying Value $ 248,273,000 347,959,000
Interest rate (as a percent) 3.60%  
Aggregate additional borrowing capacity $ 150,000,000  
Unsecured notes payable [Member]    
Debt    
Carrying Value $ 1,167,000 1,287,000
Interest rate (as a percent) 0.00%  
Unamortized discount included in carrying value $ 294,000 373,000
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member] | Minimum [Member]    
Debt    
Variable rate, spread (as a percent) 0.775%  
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member] | Maximum [Member]    
Debt    
Variable rate, spread (as a percent) 1.45%  
London Interbank Offered Rate (LIBOR) [Member] | Term Loan Facilities [Member] | Minimum [Member]    
Debt    
Variable rate, spread (as a percent) 0.85%  
London Interbank Offered Rate (LIBOR) [Member] | Term Loan Facilities [Member] | Maximum [Member]    
Debt    
Variable rate, spread (as a percent) 1.65%  
Mortgage and other secured debt [Member]    
Debt    
Carrying Value $ 170,423,000 163,838,000
Mortgage and other secured debt [Member] | Fixed rate mortgage debt [Member]    
Debt    
Carrying Value 147,141,000 150,723,000
Unamortized premium included in carrying value $ 281,000 349,000
Weighted average interest rate (as a percent) 4.17%  
Mortgage and other secured debt [Member] | Fixed rate mortgage debt [Member] | Minimum [Member]    
Debt    
Interest rate (as a percent) 3.82%  
Mortgage and other secured debt [Member] | Fixed rate mortgage debt [Member] | Maximum [Member]    
Debt    
Interest rate (as a percent) 7.87%  
Mortgage and other secured debt [Member] | Variable rate secured loans [Member]    
Debt    
Carrying Value $ 23,282,000 13,115,000
Weighted average interest rate (as a percent) 4.47%  
Mortgage and other secured debt [Member] | London Interbank Offered Rate (LIBOR) [Member] | Variable rate secured loans [Member] | Minimum [Member]    
Debt    
Variable rate, spread (as a percent) 1.85%  
Mortgage and other secured debt [Member] | London Interbank Offered Rate (LIBOR) [Member] | Variable rate secured loans [Member] | Maximum [Member]    
Debt    
Variable rate, spread (as a percent) 2.35%  
Mortgage and other secured debt [Member] | London Interbank Offered Rate (LIBOR) [Member] | Construction Loan Payable [Member]    
Debt    
Remaining borrowing capacity $ 98,400,000  
Senior Notes [Member] | 3.60% Senior Notes [Member]    
Debt    
Carrying Value 347,986,000 347,551,000
Debt instrument, face amount $ 350,000,000  
Interest rate (as a percent) 3.60%  
Unamortized discount included in carrying value $ 1,400,000 1,700,000
Effective interest rate on debt (as a percent) 3.70%  
Senior Notes [Member] | 5.250% Senior Notes [Member]    
Debt    
Carrying Value $ 247,136,000 246,645,000
Debt instrument, face amount $ 250,000,000  
Interest rate (as a percent) 5.25%  
Unamortized discount included in carrying value $ 2,600,000 3,000,000
Effective interest rate on debt (as a percent) 5.49%  
Senior Notes [Member] | 3.70% Senior Notes [Member]    
Debt    
Carrying Value $ 298,815,000 298,322,000
Debt instrument, face amount $ 300,000,000  
Interest rate (as a percent) 3.70%  
Unamortized discount included in carrying value $ 900,000 1,300,000
Effective interest rate on debt (as a percent) 3.85%  
Senior Notes [Member] | 5.0% Senior Notes [Member]    
Debt    
Carrying Value $ 297,109,000 296,731,000
Debt instrument, face amount $ 300,000,000  
Interest rate (as a percent) 5.00%  
Unamortized discount included in carrying value $ 2,400,000 2,700,000
Effective interest rate on debt (as a percent) 5.15%  
Loans Payable [Member]    
Debt    
Deferred financing costs, net $ 7,200,000 $ 5,000,000