Quarterly report pursuant to Section 13 or 15(d)

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)

v3.5.0.2
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)
$ in Thousands
Jun. 30, 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 $ 3,103 $ 1,923
Variable Interest Entity [Line Items]    
Number of self storage properties owned by VIEs | property 318  
Net book value of real estate owned by consolidated VIEs $ 1,345,227 1,079,101
Carrying value of fixed rate mortgages held by VIEs $ 748,205 564,886
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 by VIEs | property 34  
Net book value of real estate owned by consolidated VIEs $ 258,700 262,600
Mortgages [Member] | Fixed Rate Mortgages [Member]    
Variable Interest Entity [Line Items]    
Carrying value of fixed rate mortgages held by VIEs 213,283 176,911
Mortgages [Member] | Fixed Rate Mortgages [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Variable Interest Entity [Line Items]    
Carrying value of fixed rate mortgages held by VIEs 42,200 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 (5,500) (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 $ 5,500 $ 2,800