Annual report pursuant to Section 13 and 15(d)

Debt (Details)

v3.3.1.900
Debt (Details) - USD ($)
 12 Months Ended
May. 06, 2015
Apr. 20, 2015
Dec. 31, 2015
Jun. 29, 2015
Dec. 31, 2014
May. 14, 2014
Dec. 31, 2013
Debt              
Debt, net     $ 2,077,752,000   $ 1,914,036,000    
Deferred financing costs, net     5,867,000   4,849,000    
Long-term debt gross     2,097,230,000        
Mortgage and Other Secured Loans [Member]              
Debt              
Debt, net     331,000,000   422,467,000    
Fixed rate mortgage loans [Member]              
Debt              
Debt, net     $ 281,208,000   385,769,000    
Stated Interest Rates, low end of range (as a percent)     3.96%        
Stated Interest Rates, high end of range (as a percent)     7.87%        
Unamortized premium included in carrying value     $ 514,000   42,000    
Weighted average interest rate excluding incremental rate     6.08%        
Variable rate secured loans [Member]              
Debt              
Debt, net     $ 49,792,000   36,698,000    
Stated interest rate (as a percent)     2.20%        
Revolving Credit Facility [Member]              
Debt              
Debt, net     $ 43,500,000   83,000,000    
Term Loan Facilities [Member]              
Debt              
Debt, net     $ 515,900,000   517,846,000    
Weighted average interest rate (as a percent)     1.92%        
Additional borrowing capacity available provided there is no default under the agreement     $ 150,000,000        
Aggregate additional borrowing capacity     430,000,000        
Unsecured notes payable [Member]              
Debt              
Debt, net     1,500,000   1,607,000    
Unamortized discount included in carrying value     554,000   654,000    
4.25% Exchangeable Senior Notes [Member]              
Debt              
Debt, net     $ 0   572,000    
Stated interest rate (as a percent)             4.25%
Debt Instrument, Redemption, Actual Redemption Price As Percentage Of Principal   100.00%          
Unamortized discount included in carrying value         3,000    
Long-term debt gross         $ 575,000    
London Interbank Offered Rate (LIBOR) [Member] | Variable rate secured loans [Member] | Minimum [Member]              
Debt              
Variable rate, spread (as a percent)     1.85%        
London Interbank Offered Rate (LIBOR) [Member] | Variable rate secured loans [Member] | Maximum [Member]              
Debt              
Variable rate, spread (as a percent)     2.00%        
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member] | Minimum [Member]              
Debt              
Variable rate, spread (as a percent)     0.875%        
London Interbank Offered Rate (LIBOR) [Member] | Revolving Credit Facility [Member] | Maximum [Member]              
Debt              
Variable rate, spread (as a percent)     1.60%        
London Interbank Offered Rate (LIBOR) [Member] | Term Loan Facilities [Member] | Minimum [Member]              
Debt              
Variable rate, spread (as a percent)     0.90%        
London Interbank Offered Rate (LIBOR) [Member] | Term Loan Facilities [Member] | Maximum [Member]              
Debt              
Variable rate, spread (as a percent)     2.60%        
Revolving Credit Facility [Member] | Revolving Credit Facility [Member]              
Debt              
Weighted average interest rate (as a percent)     1.40%   1.47%    
Loans Payable [Member]              
Debt              
Deferred financing costs, net     $ 8,000,000   $ 6,000,000    
Line of Credit [Member] | Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]              
Debt              
Variable rate, spread (as a percent) 0.875%            
Line of Credit [Member] | Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]              
Debt              
Variable rate, spread (as a percent) 1.60%            
Senior Notes [Member] | 3.60% Senior Notes [Member]              
Debt              
Debt, net     $ 346,714,000   346,311,000    
Stated interest rate (as a percent)     3.60%        
Interest rate on debt (as a percent)     3.70%        
Unamortized discount included in carrying value     $ 2,200,000   2,500,000    
Senior Notes [Member] | 5.250% Senior Notes [Member]              
Debt              
Debt, net     $ 245,731,000   245,306,000    
Stated interest rate (as a percent)     5.25%        
Interest rate on debt (as a percent)     5.49%        
Unamortized discount included in carrying value     $ 3,800,000   4,200,000    
Senior Notes [Member] | 3.70% Senior Notes [Member]              
Debt              
Debt, net     $ 297,378,000   296,927,000    
Stated interest rate (as a percent)     3.70%     3.70%  
Interest rate on debt (as a percent)     3.85%        
Unamortized discount included in carrying value     $ 2,100,000   2,400,000    
Senior Notes [Member] | 5.0% Senior Notes [Member]              
Debt              
Debt, net     $ 296,019,000   $ 0    
Stated interest rate (as a percent)     5.00% 5.00%      
Interest rate on debt (as a percent)     5.15%        
Unamortized discount included in carrying value     $ 3,300,000        
Senior Notes [Member] | 4.25% Exchangeable Senior Notes [Member]              
Debt              
Stated interest rate (as a percent)         4.25%