Organization - Additional Information (Detail1)						3 Months Ended	6 Months Ended
	Jul. 18, 2025 USD ($)	Mar. 17, 2022 USD ($) shares	May 28, 2021 USD ($) shares	Feb. 26, 2021 USD ($)	Jan. 15, 2021 USD ($) $ / shares shares	Mar. 31, 2025 shares	Jun. 30, 2026 USD ($) Employee $ / shares shares	Dec. 31, 2025 $ / shares shares	Sep. 30, 2025 $ / shares
Organization And Nature Of Operations [Line Items]
Date of formation of company							Oct. 14, 2020
Number of employees | Employee							0
Preferred Stock, shares authorized					200,000,000			200,000,000
Preferred Stock, par value | $ / shares					$ 0.001		$ 0.001	$ 0.001
Shares issuable pursuant to distribution reinvestment plan | $	$ 75,000,000			$ 20,000,000
Maximum
Organization And Nature Of Operations [Line Items]
Common stock, value authorized | $				$ 200,000,000
Class A Common Stock
Organization And Nature Of Operations [Line Items]
Common Stock, shares authorized							230,000,000	230,000,000
Common Stock, par value | $ / shares							$ 0.001	$ 0.001
Class A Common Stock | Primary Offering | Maximum
Organization And Nature Of Operations [Line Items]
Common stock, value authorized | $			$ 1,000,000,000
Class A Common Stock | Pubic Offering
Organization And Nature Of Operations [Line Items]
Common Stock, shares authorized			300,000,000
Shares issuable pursuant to distribution reinvestment plan | $			$ 95,000,000
Class A Common Stock | Pubic Offering | Common Stock
Organization And Nature Of Operations [Line Items]
Common stock issued in connection with offering							2,900,000
Class A Common Stock | Private Offering
Organization And Nature Of Operations [Line Items]
Gross proceeds from issuance of common stock | $							$ 30,300,000
Class P Common Stock
Organization And Nature Of Operations [Line Items]
Common Stock, shares authorized							30,000,000	30,000,000
Common Stock, par value | $ / shares							$ 0.001	$ 0.001
Gross proceeds from issuance of common stock | $		$ 100,700,000
Class P Common Stock | Common Stock
Organization And Nature Of Operations [Line Items]
Common stock issued in connection with offering						64,865
Class P Common Stock | Pubic Offering
Organization And Nature Of Operations [Line Items]
Common Stock, shares authorized			30,000,000
Class P Common Stock | Private Offering | Common Stock
Organization And Nature Of Operations [Line Items]
Common stock issued in connection with offering		10,600,000
Class T Common Stock
Organization And Nature Of Operations [Line Items]
Common Stock, shares authorized							100,000,000	100,000,000
Common Stock, par value | $ / shares							$ 0.001	$ 0.001
Class T Common Stock | Primary Offering | Maximum
Organization And Nature Of Operations [Line Items]
Common stock, value authorized | $			$ 1,000,000,000
Class T Common Stock | Pubic Offering
Organization And Nature Of Operations [Line Items]
Common Stock, shares authorized			300,000,000
Shares issuable pursuant to distribution reinvestment plan | $			$ 95,000,000
Class T Common Stock | Private Offering
Organization And Nature Of Operations [Line Items]
Gross proceeds from issuance of common stock | $							$ 48,100,000
Class T Common Stock | Private Offering | Common Stock
Organization And Nature Of Operations [Line Items]
Common stock issued in connection with offering							4,800,000
Class W Common Stock
Organization And Nature Of Operations [Line Items]
Common Stock, shares authorized							70,000,000	70,000,000
Common Stock, par value | $ / shares							$ 0.001	$ 0.001
Class W Common Stock | Primary Offering | Maximum
Organization And Nature Of Operations [Line Items]
Common stock, value authorized | $			$ 1,000,000,000
Class W Common Stock | Pubic Offering
Organization And Nature Of Operations [Line Items]
Common Stock, shares authorized			70,000,000
Shares issuable pursuant to distribution reinvestment plan | $			$ 95,000,000
Class W Common Stock | Private Offering
Organization And Nature Of Operations [Line Items]
Gross proceeds from issuance of common stock | $							$ 6,300,000
Class W Common Stock | Private Offering | Common Stock
Organization And Nature Of Operations [Line Items]
Common stock issued in connection with offering							700,000
Series E Preferred Offering
Organization And Nature Of Operations [Line Items]
Preferred Stock, par value | $ / shares									$ 0.001
Preferred stock offering price | $ / shares									$ 10
Common stock issued in connection with offering							98,000
Articles of Incorporation
Organization And Nature Of Operations [Line Items]
Common Stock, shares authorized					30,000
Common Stock, par value | $ / shares					$ 0.001
Articles of Amendment and Restatement
Organization And Nature Of Operations [Line Items]
Common Stock, shares authorized					700,000,000
Common Stock, par value | $ / shares					$ 0.001
Strategic Storage Advisor IV, LLC
Organization And Nature Of Operations [Line Items]
Sale of common shares to advisor | $					$ 1,000
Strategic Storage Advisor IV, LLC | Class A Common Stock
Organization And Nature Of Operations [Line Items]
Number of shares sold to advisor					110
SmartStop REIT Advisors, LLC | Strategic Storage Advisor IV, LLC
Organization And Nature Of Operations [Line Items]
Percentage of economic interests owned by sponsor							100.00%
SmartStop REIT Advisors, LLC | Strategic Storage Property Management VI, LLC
Organization And Nature Of Operations [Line Items]
Percentage of Property Management owned by sponsor							100.00%