Quarterly report pursuant to Section 13 or 15(d)

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Principles of Consolidation (Details)

v3.22.2.2
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Principles of Consolidation (Details)
$ in Thousands
Sep. 30, 2022
USD ($)
partnership
property
Dec. 31, 2021
USD ($)
Variable Interest Entity [Line Items]    
Number of self storage properties | property 1,100  
Net book value of real estate owned $ 5,623,438 $ 5,219,471
Carrying value of fixed rate mortgages 3,497,688 2,948,944
Fixed rate mortgages payable | Fixed rate mortgages payable    
Variable Interest Entity [Line Items]    
Carrying value of fixed rate mortgages $ 300,688 303,944
VIE, Primary Beneficiary    
Variable Interest Entity [Line Items]    
Number of partnerships considered to be VIEs | partnership 22  
Number of self storage properties | property 48  
Net book value of real estate owned $ 415,400 425,700
VIE, Primary Beneficiary | Fixed rate mortgages payable | Fixed rate mortgages payable    
Variable Interest Entity [Line Items]    
Carrying value of fixed rate mortgages $ 188,700 $ 188,700