Annual report pursuant to Section 13 and 15(d)

SUBSEQUENT EVENTS - Self Storage Property Acquisitions (Details)

v3.10.0.1
SUBSEQUENT EVENTS - Self Storage Property Acquisitions (Details)
$ in Millions
 2 Months Ended 12 Months Ended
Feb. 25, 2019
USD ($)
property
shares
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
property
Participating Regional Operator [Member] | Management [Member]          
Subsequent Event [Line Items]          
Number of self storage properties acquired | property         16
Participating Regional Operator [Member] | Due Diligence Costs [Member] | Management [Member]          
Subsequent Event [Line Items]          
Due diligence expenses payable to the PROs   $ 0.4 $ 0.7 $ 1.1  
Subsequent Event [Member] | Participating Regional Operator [Member] | Due Diligence Costs [Member] | Management [Member]          
Subsequent Event [Line Items]          
Due diligence expenses payable to the PROs $ 0.1        
Subsequent Event [Member] | Acquisition of Self Storage Properties [Member]          
Subsequent Event [Line Items]          
Number of self storage properties acquired | property 23        
Aggregate purchase price $ 147.0        
Consideration given, net cash 122.9        
Assumed working capital liabilities 0.4        
Consideration given, value of OP Equity $ 23.7        
Subsequent Event [Member] | Acquisition of Self Storage Properties [Member] | Series A-1 Preferred Units [Member]          
Subsequent Event [Line Items]          
Consideration, equity interest issued (in shares) | shares 158,199        
Subsequent Event [Member] | Acquisition of Self Storage Properties [Member] | OP units [Member]          
Subsequent Event [Line Items]          
Consideration, equity interest issued (in shares) | shares 58,942        
Subsequent Event [Member] | Acquisition of Self Storage Properties [Member] | Subordinated performance units [Member]          
Subsequent Event [Line Items]          
Consideration, equity interest issued (in shares) | shares 692,075