v3.25.3
Document and Entity Information - shares
 9 Months Ended
Sep. 30, 2025
Nov. 03, 2025
Document Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 30, 2025  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q3  
Title of 12(b) Security Common Stock, $0.001 par value  
Trading Symbol SMA  
Security Exchange Name NYSE  
Entity Registrant Name SmartStop Self Storage REIT, Inc.  
Entity Central Index Key 0001585389  
Entity Current Reporting Status Yes  
Current Fiscal Year End Date --12-31  
Entity Filer Category Non-accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Incorporation, State or Country Code MD  
Document Quarterly Report true  
Document Transition Report false  
Entity File Number 001-42584  
Entity Tax Identification Number 46-1722812  
Entity Address, Address Line One 10 Terrace Road  
Entity Address, City or Town Ladera Ranch  
Entity Address, State or Province CA  
Entity Address, Postal Zip Code 92694  
City Area Code 866  
Local Phone Number 418-5144  
Entity Interactive Data Current Yes  
Entity Common Stock, Shares Outstanding   55,363,743