Annual report pursuant to Section 13 and 15(d)

SELF STORAGE PROPERTY ACQUISITIONS AND DISPOSITIONS - Pro Forma Information (Details)

v3.8.0.1
SELF STORAGE PROPERTY ACQUISITIONS AND DISPOSITIONS - Pro Forma Information (Details)
$ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2016
property
Sep. 30, 2016
property
Jun. 30, 2016
property
Mar. 31, 2016
property
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
property
Dec. 31, 2015
USD ($)
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]              
Acquisition costs | $         $ 593 $ 6,546 $ 4,765
Credit Facility [Member] | Line of Credit [Member] | Revolving line of credit [Member]              
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]              
Effective interest rate (percent) 2.17%       2.96% 2.17%  
2016 Acquisitions [Member]              
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]              
Number of self storage properties acquired | property 31 34 25 17   107  
Number of businesses acquired for which pro forma financial information is available | property           100  
Number of businesses acquired for which pro forma financial information is not available | property           7  
Pro forma revenue | $           $ 35,500 61,200
Pro forma net income (loss) | $           $ 15,300 $ (23,100)