Quarterly report pursuant to Section 13 or 15(d)

Shareholders' Equity - Additional Information (Detail)

v3.20.2
Shareholders' Equity - Additional Information (Detail)
3 Months Ended 6 Months Ended 12 Months Ended
Mar. 31, 2020
Property
Jun. 30, 2020
USD ($)
Property
$ / shares
shares
Jun. 30, 2019
shares
Dec. 31, 2019
shares
Jun. 14, 2018
USD ($)
Aug. 02, 2017
USD ($)
Stockholders Equity [Line Items]            
Common stock value authorized under equity offering program         $ 300,000,000  
Number of storage facilities acquired | Property 6 6        
Buyback Program, authorized repurchase amount           $ 200,000,000
Stock repurchased during period, shares | shares   0   0    
Shares issued under Dividend Reinvestment Plan | shares   0 0      
Equity Program [Member]            
Stockholders Equity [Line Items]            
Common stock shares issued under equity offering program | shares   190,403 0      
Weighted average issue price | $ / shares   $ 114.26        
Proceeds from issuance of common stock   $ 21,500,000        
Other expenses   100,000        
Equity Program [Member] | SunTrust [Member]            
Stockholders Equity [Line Items]            
Sales commissions paid   $ 200,000