Quarterly report pursuant to Section 13 or 15(d)

Recent Accounting Pronouncements - Additional Information (Detail)

v3.19.1
Recent Accounting Pronouncements - Additional Information (Detail)
3 Months Ended
Mar. 31, 2019
USD ($)
Property
Jan. 01, 2019
USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Number of leased real estate properties under extension options, operates for self-storage facilities | Property 2  
Number of leased properties under purchase options | Property 1  
Option to purchase property under lease $ 13,300,000  
Operating lease expenses $ 600,000  
Weighted average remaining lease term 10 years 8 months 12 days  
Weighted average discount rate 5.30%  
Finance Lease, Liability $ 0  
Operating lease commitments 19,864,000  
ASU 2016-02 [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Right-of-use assets and related lease liabilities   $ 16,000,000
Operating lease, aggregate right-of-use assets $ 15,500,000  
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List] us-gaap:OtherAssetsMember  
Operating lease liabilities $ 15,300,000  
Operating Lease, Liability, Statement of Financial Position [Extensible List] us-gaap:AccountsPayableAndAccruedLiabilitiesMember  
Minimum [Member] | ASU 2016-02 [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Percentage of remaining economic life of asset to define the lease term, major part 75.00%  
Percentage of fair value of underlying asset to define the lease term, substantially all 90.00%  
Minimum [Member] | Revenue [Member] | Product Concentration [Member] | Revenue From Rental Products [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Concentration risk, percentage 90.00%  
Maximum [Member] | ASU 2016-02 [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Percentage of total economic life of underlying asset to define the lease term, at or near the end 25.00%