Quarterly report pursuant to Section 13 or 15(d)

Investment in Joint Ventures - Summary of Company's Unconsolidated Joint Ventures (Parenthetical) (Detail)

v3.19.1
Investment in Joint Ventures - Summary of Company's Unconsolidated Joint Ventures (Parenthetical) (Detail)
3 Months Ended
Mar. 31, 2019
USD ($)
Property
Mar. 31, 2018
USD ($)
Schedule of Equity Method Investments [Line Items]    
Distributions from unconsolidated joint ventures | $ $ 2,404,000 $ 2,037,000
Number of storage facilities acquired 2  
Sovran HHF Storage Holdings LLC [Member]    
Schedule of Equity Method Investments [Line Items]    
Non-recourse mortgage loan principal outstanding | $ $ 219,600,000  
Distributions from unconsolidated joint ventures | $ 1,700,000  
Excess of investment over net asset due to capitalization of acquisition related costs | $ $ 1,700,000  
Sovran HHF Storage Holdings LLC [Member] | Arizona [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 11  
Sovran HHF Storage Holdings LLC [Member] | Colorado [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 4  
Sovran HHF Storage Holdings LLC [Member] | Florida [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 3  
Sovran HHF Storage Holdings LLC [Member] | Georgia [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 1  
Sovran HHF Storage Holdings LLC [Member] | Kentucky [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 2  
Sovran HHF Storage Holdings LLC [Member] | Nevada [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 5  
Sovran HHF Storage Holdings LLC [Member] | New Jersey [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 2  
Sovran HHF Storage Holdings LLC [Member] | Ohio [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 6  
Sovran HHF Storage Holdings LLC [Member] | Pennsylvania [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 1  
Sovran HHF Storage Holdings LLC [Member] | Tennessee [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 2  
Sovran HHF Storage Holdings LLC [Member] | Texas [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 20  
Sovran HHF Storage Holdings II LLC [Member]    
Schedule of Equity Method Investments [Line Items]    
Non-recourse mortgage loan principal outstanding | $ $ 87,800,000  
Distributions from unconsolidated joint ventures | $ $ 500,000  
Sovran HHF Storage Holdings II LLC [Member] | New Jersey [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 17  
Sovran HHF Storage Holdings II LLC [Member] | Pennsylvania [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 3  
Sovran HHF Storage Holdings II LLC [Member] | Texas [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 10  
191 III Life Storage Holdings LLC [Member]    
Schedule of Equity Method Investments [Line Items]    
Distributions from unconsolidated joint ventures | $ $ 100,000  
Contribution of company to joint venture as share in capital | $ 100,000  
191 III Life Storage Holdings LLC [Member] | California [Member]    
Schedule of Equity Method Investments [Line Items]    
Non-recourse mortgage loan principal outstanding | $ $ 57,200,000  
191 III Life Storage Holdings LLC [Member] | California [Member] | Storage Facilities [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of storage facilities acquired 6  
Life Storage-SERS Storage LLC [Member]    
Schedule of Equity Method Investments [Line Items]    
Contribution of company to joint venture as share in capital | $ $ 0  
Life Storage-SERS Storage LLC [Member] | Georgia [Member]    
Schedule of Equity Method Investments [Line Items]    
Non-recourse mortgage loan principal outstanding | $ $ 22,000,000  
Life Storage-SERS Storage LLC [Member] | Georgia [Member] | Storage Facilities [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of storage facilities acquired 3  
Life Storage-HIERS Storage LLC [Member]    
Schedule of Equity Method Investments [Line Items]    
Non-recourse mortgage loan principal outstanding | $ $ 45,400,000  
Distributions from unconsolidated joint ventures | $ $ 100,000  
Life Storage-HIERS Storage LLC [Member] | Arizona [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 2  
Life Storage-HIERS Storage LLC [Member] | Florida [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 1  
Life Storage-HIERS Storage LLC [Member] | Texas [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 7  
Life Storage-HIERS Storage LLC [Member] | North Carolina [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 1  
Life Storage-HIERS Storage LLC [Member] | VIRGINIA    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 1  
Iskalo Office Holdings, LLC [Member]    
Schedule of Equity Method Investments [Line Items]    
Rent paid during the period | $ $ 300,000 $ 300,000
Urban Box Coralway Storage, LLC [Member]    
Schedule of Equity Method Investments [Line Items]    
Non-recourse mortgage loan principal outstanding | $ 6,700,000  
SNL/Orix 1200 McDonald Ave., LLC [Member]    
Schedule of Equity Method Investments [Line Items]    
Non-recourse mortgage loan principal outstanding | $ $ 11,600,000  
SNL/Orix 1200 McDonald Ave., LLC [Member] | New York [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 1  
SNL Orix Merrick, LLC [Member]    
Schedule of Equity Method Investments [Line Items]    
Non-recourse mortgage loan principal outstanding | $ $ 12,300,000  
SNL Orix Merrick, LLC [Member] | New York [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 1  
N 32nd Street Self Storage, LLC [Member] | Arizona [Member]    
Schedule of Equity Method Investments [Line Items]    
Number of self-storage facilities 1  
Non-recourse mortgage loan principal outstanding | $ $ 6,300,000  
Bluebird Sanford Storage LP [Member]    
Schedule of Equity Method Investments [Line Items]    
Non-recourse mortgage loan principal outstanding | $ 3,200,000  
Bluebird Sanford Storage LP [Member] | Common Stock Shares [Member]    
Schedule of Equity Method Investments [Line Items]    
Contribution of company to joint venture as share in capital | $ 300,000  
Bluebird Ingram Storage LP [Member]    
Schedule of Equity Method Investments [Line Items]    
Non-recourse mortgage loan principal outstanding | $ 17,600,000  
Bluebird Ingram Storage LP [Member] | Common Stock Shares [Member]    
Schedule of Equity Method Investments [Line Items]    
Contribution of company to joint venture as share in capital | $ $ 1,300,000