Secured Debt - Additional Information (Detail) $ in Millions													3 Months Ended
		May 10, 2023 CAD ($)	May 02, 2023 USD ($)	Apr. 13, 2023 USD ($)	Jan. 31, 2023 USD ($)	Dec. 20, 2022 USD ($)	Sep. 20, 2022 CAD ($)	May 26, 2022 USD ($)	May 17, 2022 USD ($)	Apr. 26, 2022 USD ($)	Dec. 30, 2021 USD ($)	Nov. 30, 2021 USD ($) SpecialEntity	Mar. 31, 2023 USD ($)	Apr. 14, 2023	Jan. 31, 2023 CAD ($)	Dec. 20, 2022 CAD ($)	Dec. 19, 2022 USD ($)	Sep. 21, 2022 USD ($)	Jul. 08, 2022 USD ($)	Jul. 08, 2021 USD ($)
Line Of Credit Facility [Line Items]
Weighted average interest rate													7.42%
CDOR
Line Of Credit Facility [Line Items]
Notional amount	[1]												$ 25,000,000
SmartStop Delayed Draw Mezzanine Loan Agreement | Subsequent Event
Line Of Credit Facility [Line Items]
Repaid outstanding balance			$ 50,000,000
SmartStop Delayed Draw Mezzanine Loan Agreement | St. John Property
Line Of Credit Facility [Line Items]
Additional borrowings from credit facility																			$ 7,200,000
SmartStop Delayed Draw Mezzanine Loan Agreement | Oxford Property
Line Of Credit Facility [Line Items]
Additional borrowings from credit facility																		$ 11,000,000.0
Huntington Credit Facility
Line Of Credit Facility [Line Items]
Number of Special Purpose Entities | SpecialEntity												3
Line of credit facility, maximum borrowing capacity												$ 50,000,000
Term loan maturity date												Nov. 30, 2024	Nov. 30, 2024
Applicable interest rate													7.41%
Line of credit facility, amount borrowed										$ 12,900,000	$ 14,700,000	$ 22,400,000
Huntington Credit Facility | Subsequent Event
Line Of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity				$ 107,600,000
Term loan maturity date				Nov. 30, 2025
Line of credit facility, amount borrowed				$ 12,500,000
Debt Instrument, Interest Rate, Effective Percentage														6.00%
Huntington Credit Facility | Floor
Line Of Credit Facility [Line Items]
Applicable interest rate												3.25%
Huntington Credit Facility | Secured Overnight Financing Rate
Line Of Credit Facility [Line Items]
Debt instrument variable interest rate												2.61%
Interest rate term													1 month Term
Debt instrument, basis spread on variable rate												2.61%
Huntington Credit Facility | Second Amendment
Line Of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity									$ 100,000,000
Line of credit facility, amount borrowed								$ 30,600,000	14,500,000
Line of credit, additional borrowing capacity									$ 50,000,000
Huntington Credit Facility | Interest Rate Swap Agreement | Subsequent Event
Line Of Credit Facility [Line Items]
Notional amount				$ 60,000,000.0
Huntington Credit Facility | Interest Rate Swap Agreement | Secured Overnight Financing Rate | Subsequent Event
Line Of Credit Facility [Line Items]
Applicable interest rate				4.01%
Huntington Credit Facility | Interest Rate Cap | Subsequent Event
Line Of Credit Facility [Line Items]
Notional amount				$ 47,600,000
Huntington Credit Facility | Interest Rate Cap | Secured Overnight Financing Rate | Subsequent Event
Line Of Credit Facility [Line Items]
Applicable interest rate				2.60%
Huntington Bridge Loan
Line Of Credit Facility [Line Items]
Debt instrument carrying amount										$ 30,600,000
Debt instrument maturity date										Jul. 25, 2022
Huntington Bridge Loan | Floor
Line Of Credit Facility [Line Items]
Applicable interest rate										3.25%
Huntington Bridge Loan | Secured Overnight Financing Rate
Line Of Credit Facility [Line Items]
Debt instrument variable interest rate										2.61%
Debt instrument, basis spread on variable rate										2.61%
Skymar Loan
Line Of Credit Facility [Line Items]
Term loan maturity date													Aug. 01, 2024							Aug. 01, 2024
Applicable interest rate													4.125%							4.125%
Mortgage loan, amount																				$ 4,800,000
Loans from SmartStop OP, L.P. | SmartStop Delayed Draw Mezzanine Loan Agreement | Bradenton Property and Apopka Property
Line Of Credit Facility [Line Items]
Commitment fee percentage											1.00%
Line of credit facility, amount borrowed											$ 6,800,000
Loans from SmartStop OP, L.P. | SmartStop Delayed Draw Mezzanine Loan Agreement | Cambridge Property
Line Of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity						$ 55,000,000.0											$ 45,000,000.0
Line of credit facility, amount borrowed						$ 10,000,000.0
Loans from SmartStop OP, L.P. | SmartStop Delayed Draw Mezzanine Loan Agreement | Edmonton Property
Line Of Credit Facility [Line Items]
Applicable interest rate													7.87%
Additional borrowings from credit facility					$ 15,000,000.0
Loans from SmartStop OP, L.P. | SmartStop Delayed Draw Mezzanine Loan Agreement | Secured Overnight Financing Rate | Cambridge Property
Line Of Credit Facility [Line Items]
Debt instrument, description of variable rate basis						SOFR plus 3%
Loans from SmartStop OP, L.P. | Maximum | SmartStop Delayed Draw Mezzanine Loan Agreement | Bradenton Property and Apopka Property
Line Of Credit Facility [Line Items]
Loan in connection with acquisition of Bradenton Property and Apopka Property											$ 45,000,000
National Bank of Canada Loan | Acquisition of North York Property
Line Of Credit Facility [Line Items]
Debt instrument carrying amount															$ 25.0
National Bank of Canada Loan | CDOR | Acquisition of North York Property
Line Of Credit Facility [Line Items]
Debt instrument variable interest rate					2.40%
Interest rate term					one month
Debt instrument, basis spread on variable rate					2.40%
National Bank of Canada Loan | Interest Rate Swap Agreement | Acquisition of North York Property
Line Of Credit Facility [Line Items]
Notional amount															$ 25.0
Debt instrument maturity date					Jan. 31, 2025
Debt instrument, frequency of payment					monthly
Debt instrument amortization period					25 years
National Bank of Canada Loan | Interest Rate Swap Agreement | CDOR | Acquisition of North York Property
Line Of Credit Facility [Line Items]
Applicable interest rate					3.79%										3.79%
National Bank of Canada | Cambridge Property
Line Of Credit Facility [Line Items]
Term loan																$ 15.5
National Bank of Canada | Cambridge Property | Subsequent Event
Line Of Credit Facility [Line Items]
Repaid outstanding balance		$ 0.4
National Bank of Canada | Burlington Property
Line Of Credit Facility [Line Items]
Term loan							$ 16.5
National Bank of Canada | CDOR | Cambridge Property
Line Of Credit Facility [Line Items]
Debt instrument variable interest rate						2.25%
Interest rate term						one month
Debt instrument, basis spread on variable rate						2.25%
National Bank of Canada | CDOR | Burlington Property
Line Of Credit Facility [Line Items]
Debt instrument variable interest rate							2.25%
Interest rate term							one month
Debt instrument, basis spread on variable rate							2.25%
National Bank of Canada | Interest Rate Swap Agreement | Cambridge Property
Line Of Credit Facility [Line Items]
Notional amount																$ 15.5
Debt instrument maturity date						Dec. 20, 2025
Debt instrument, frequency of payment						monthly
Debt instrument amortization period						25 years
National Bank of Canada | Interest Rate Swap Agreement | Burlington Property
Line Of Credit Facility [Line Items]
Notional amount							$ 16.5
Debt instrument maturity date							Sep. 20, 2025
Debt instrument, frequency of payment							monthly
Debt instrument amortization period							25 years
National Bank of Canada | Interest Rate Swap Agreement | CDOR | Cambridge Property
Line Of Credit Facility [Line Items]
Applicable interest rate						3.84%										3.84%
National Bank of Canada | Interest Rate Swap Agreement | CDOR | Burlington Property
Line Of Credit Facility [Line Items]
Applicable interest rate							4.02%
Extended Maturity | Huntington Credit Facility
Line Of Credit Facility [Line Items]
Term loan maturity date												Nov. 30, 2026
Extended Maturity | Loans from SmartStop OP, L.P. | SmartStop Delayed Draw Mezzanine Loan Agreement | Cambridge Property
Line Of Credit Facility [Line Items]
Debt instrument maturity date						Dec. 30, 2023

[1] Notional amount is denominated in CAD and has been designated as a cash flow hedge.