Quarterly report pursuant to Section 13 or 15(d)

ORGANIZATION AND NATURE OF OPERATIONS (Details)

v3.5.0.2
ORGANIZATION AND NATURE OF OPERATIONS (Details)
$ / shares in Units, storage_unit in Thousands, $ in Thousands, ft² in Millions
9 Months Ended
Jul. 06, 2016
USD ($)
$ / shares
shares
Apr. 28, 2015
USD ($)
$ / shares
shares
Sep. 30, 2016
USD ($)
ft²
storage_unit
state
property
$ / shares
shares
Sep. 30, 2015
USD ($)
Dec. 31, 2015
$ / shares
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]          
Common shares of beneficial interest, par value (in dollars per share) | $ / shares     $ 0.01   $ 0.01
Proceeds from issuance of common shares | $ $ 237,500   $ 238,712 $ 278,070  
Number of self storage properties | property     352    
Number of states that self storage properties are owned in | state     19    
Total rentable square feet in self storage properties | ft²     21.0    
Number of storage units owned | storage_unit     168    
Common Shares [Member]          
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]          
Issuance of common shares (in shares) | shares     12,046,250    
Common shares of beneficial interest, par value (in dollars per share) | $ / shares     $ 0.01    
Net proceeds from issuance of common shares in IPO | $   $ 278,100      
IPO [Member] | Common Shares [Member]          
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]          
Issuance of common shares (in shares) | shares   23,000,000      
Public offering share price (in dollars per share) | $ / shares   $ 13.00      
Over-Allotment Option [Member] | Common Shares [Member]          
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]          
Issuance of common shares (in shares) | shares 1,571,250 3,000,000      
Follow On Offering [Member] | Common Shares [Member]          
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]          
Issuance of common shares (in shares) | shares 12,046,250        
Public offering share price (in dollars per share) | $ / shares $ 20.75