Quarterly report pursuant to Section 13 or 15(d)

Investment in Storage Facilities - Additional Information (Detail)

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Investment in Storage Facilities - Additional Information (Detail)
$ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2016
USD ($)
Facility
Property
Store
Mar. 31, 2015
USD ($)
Dec. 31, 2015
USD ($)
Property
Investment Holdings [Line Items]      
Number of storage facilities acquired | Facility 25    
Stores acquired at certificate of occupancy | Store 1    
Cash paid for properties acquired $ 326,000    
Deposits paid at the time of contract     $ 2,500
Acquisition costs 2,384 $ 582  
Issuance of Operating Partnership Units $ 4,500    
Amortization period for in-place customer leases on a straight-line basis 12 months    
Amortization expense related to in-place customer leases $ 1,200 1,000  
Amortization expense expected for 2016 5,200    
Amortization expense expected for 2017 $ 500    
Net proceeds from the sale of storage facilities   711  
(Loss) gain on sale of storage facilities   $ (7)  
Acquisitions 2016 [Member]      
Investment Holdings [Line Items]      
Number of storage facilities acquired | Property 25    
Cash paid for properties acquired $ 326,048    
Acquisition costs $ 2,384   $ 345
Property Dispositions [Member]      
Investment Holdings [Line Items]      
Number of properties sold | Property     3
Carrying value of properties sold     $ 5,100
Net proceeds from the sale of storage facilities     4,600
(Loss) gain on sale of storage facilities     $ (500)