Annual report pursuant to Section 13 and 15(d)

Unsecured Line of Credit and Term Notes - Additional Information (Detail)

v3.22.0.1
Unsecured Line of Credit and Term Notes - Additional Information (Detail) - USD ($)
12 Months Ended
Oct. 07, 2021
Oct. 09, 2020
Sep. 23, 2020
Jun. 03, 2019
Dec. 07, 2017
Jul. 21, 2016
Jun. 20, 2016
Apr. 08, 2014
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2011
Debt Instrument [Line Items]                        
Amount available on unsecured revolving line of credit                 $ 499,900,000      
Unamortized senior term note discount                 11,154,000 $ 6,710,000    
Underwriting discount and other offering expenses                 5,114,000 3,490,000 $ 3,099,000  
Amortization expense related to deferred debt issuance costs                 $ 4,513,000 $ 4,096,000 3,900,000  
Maximum [Member]                        
Debt Instrument [Line Items]                        
Leverage ratio percentage                 60.00%      
Indenture covenant percentage on unencumbered assets                 150.00%      
Minimum [Member]                        
Debt Instrument [Line Items]                        
Interest coverage ratio on debt                 1.5      
Secured Debt [Member] | Maximum [Member]                        
Debt Instrument [Line Items]                        
Leverage ratio percentage                 40.00%      
Term Note [Member]                        
Debt Instrument [Line Items]                        
Debt instrument variable interest rate                 1.10% 1.14%    
Term Note [Member] | LIBOR [Member]                        
Debt Instrument [Line Items]                        
Basis spread over LIBOR                 1.00%      
Senior Term Note Due October 15, 2031 [Member] | Unsecured Senior Notes [Member]                        
Debt Instrument [Line Items]                        
Debt instrument principal amount $ 600,000,000                      
Debt instrument,maturity date Oct. 15, 2031                      
Debt instrument stated interest rate 2.40%                      
Debt instrument percentage discount to par 0.917%                      
Debt instrument, interest payable description                 Interest on the 2031 Senior Notes is payable semi-annually in arrears on each April 15 and October 15, commencing with April 15, 2022.      
Unamortized senior term note discount $ 5,500,000                      
Underwriting discount and other offering expenses 5,100,000                      
Proceeds from senior notes, net $ 589,400,000                      
Senior Term Note Due October 15, 2030 [Member] | Unsecured Senior Notes [Member]                        
Debt Instrument [Line Items]                        
Debt instrument principal amount     $ 400,000,000                  
Debt instrument,maturity date     Oct. 15, 2030                  
Debt instrument stated interest rate     2.20%                  
Debt instrument percentage discount to par     0.476%                  
Debt instrument, interest payable description                 Interest on the 2030 Senior Notes is payable semi-annually in arrears on each April 15 and October 15.      
Unamortized senior term note discount     $ 1,900,000                  
Underwriting discount and other offering expenses     3,500,000                  
Proceeds from senior notes, net     $ 394,600,000                  
Senior Term Note Due June 15, 2029 [Member] | Unsecured Senior Notes [Member]                        
Debt Instrument [Line Items]                        
Debt instrument principal amount       $ 350,000,000                
Debt instrument,maturity date       Jun. 15, 2029                
Debt instrument stated interest rate       4.00%                
Debt instrument percentage discount to par       0.524%                
Debt instrument, interest payable description                 Interest on the 2029 Senior Notes is payable semi-annually in arrears on each June 15 and December 15.      
Unamortized senior term note discount       $ 1,800,000                
Underwriting discount and other offering expenses       3,100,000                
Proceeds from senior notes, net       $ 345,100,000                
Senior Term Note Due December 15, 2027 [Member] | Unsecured Senior Notes [Member]                        
Debt Instrument [Line Items]                        
Debt instrument principal amount         $ 450,000,000              
Debt instrument,maturity date         Dec. 15, 2027              
Debt instrument stated interest rate         3.875%              
Debt instrument percentage discount to par         0.477%              
Debt instrument, interest payable description                 Interest on the 2027 Senior Notes is payable semi-annually in arrears on June 15 and December 15.      
Unamortized senior term note discount         $ 2,100,000              
Underwriting discount and other offering expenses         4,000,000.0              
Proceeds from senior notes, net         $ 443,900,000              
Senior Term Note Due July 1, 2026 [Member] | Unsecured Senior Notes [Member]                        
Debt Instrument [Line Items]                        
Debt instrument principal amount             $ 600,000,000          
Debt instrument,maturity date             Jul. 01, 2026          
Debt instrument stated interest rate             3.50%          
Debt instrument percentage discount to par             0.553%          
Debt instrument, interest payable description                 Interest on the 2026 Senior Notes is payable semi-annually in arrears on January 1 and July 1.      
Unamortized senior term note discount             $ 3,300,000          
Underwriting discount and other offering expenses             5,500,000          
Proceeds from senior notes, net             $ 591,200,000          
Term Note Due July 21, 2028 [Member]                        
Debt Instrument [Line Items]                        
Debt instrument,maturity date           Jul. 21, 2028            
Debt instrument stated interest rate           3.67%            
Additional secured term note           $ 200,000,000            
Term Note Due April 8, 2024 [Member]                        
Debt Instrument [Line Items]                        
Debt instrument,maturity date               Apr. 08, 2024        
Debt instrument stated interest rate               4.533%        
Additional secured term note               $ 175,000,000        
Term Note Due April 8, 2024 [Member] | Maximum [Member]                        
Debt Instrument [Line Items]                        
Debt instrument stated interest rate               6.283%        
Term Note Due August 5, 2021 [Member]                        
Debt Instrument [Line Items]                        
Debt instrument,maturity date                       Aug. 05, 2021
Debt instrument stated interest rate                       5.54%
Additional secured term note                       $ 100,000,000
Repayments of term debt   $ 100,000,000                    
Debt instrument whole payment required as a result of paying off term note prior to its maturity   $ 4,000,000.0                    
Senior Notes and Term Notes [Member]                        
Debt Instrument [Line Items]                        
Amortization expense related to deferred debt issuance costs                 $ 2,500,000 $ 2,400,000 $ 2,300,000  
Revolving Credit Facility [Member]                        
Debt Instrument [Line Items]                        
Revolving credit limit                 $ 500,000,000      
Line of credit facility, expiration date                 Mar. 10, 2023      
Facility fee                 0.15% 0.15%    
Interest rate, line of credit facility                 1.05% 1.09%    
Revolving Credit Facility [Member] | LIBOR [Member]                        
Debt Instrument [Line Items]                        
Basis spread over LIBOR                 0.95% 0.95%    
Revolving Credit Facility [Member] | Term Note Due June 4, 2020 [Member]                        
Debt Instrument [Line Items]                        
Basis spread over LIBOR                   1.00%    
Debt instrument principal amount                 $ 100,000,000      
Debt instrument,maturity date                 Jun. 04, 2020      
Revolving Credit Facility [Member] | Term Note [Member]                        
Debt Instrument [Line Items]                        
Revolving credit limit                 $ 900,000,000