Quarterly report pursuant to Section 13 or 15(d)

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)

v3.4.0.3
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)
$ in Thousands
Mar. 31, 2016
USD ($)
partnership
property
Dec. 31, 2015
USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Debt issuance costs reclassed from assets to liabilities following adoption of ASU 2015-03 $ 1,530 $ 1,923
Variable Interest Entity [Line Items]    
Number of self storage properties owned | property 293  
Self storage properties, net $ 1,157,731 1,079,101
Debt $ 631,676 564,886
Variable Interest Entity, Primary Beneficiary [Member]    
Variable Interest Entity [Line Items]    
Number Of Partnerships Considered Variable Interest Entities | partnership 21  
Number of self storage properties owned | property 34  
Self storage properties, net $ 260,600 262,600
Mortgages [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Variable Interest Entity [Line Items]    
Debt 42,800  
Mortgages [Member] | Fixed Rate Mortgages [Member]    
Variable Interest Entity [Line Items]    
Debt 172,201 176,911
Mortgages [Member] | Fixed Rate Mortgages [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Variable Interest Entity [Line Items]    
Debt   43,200
Accounting Standards Updated 2015-03 [Member] | Assets [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Debt issuance costs reclassed from assets to liabilities following adoption of ASU 2015-03 (2,600) (2,800)
Accounting Standards Updated 2015-03 [Member] | Debt Financing [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Debt issuance costs reclassed from assets to liabilities following adoption of ASU 2015-03 $ 2,600 $ 2,800