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Summary of Significant Accounting Policies - Additional Information (Detail) shares in Millions |  | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Mar. 01, 2022 | Sep. 30, 2023 USD ($) | Sep. 30, 2022 USD ($) | Sep. 30, 2023 USD ($) Trademark Segment | Sep. 30, 2022 USD ($) | Dec. 31, 2022 USD ($) Segment Trademark shares | Dec. 31, 2021 USD ($) shares | Dec. 31, 2020 USD ($) shares
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Payments to acquire intangible assets |  |  |  | $ 0 | $ 10,500,000 | $ 10,500,000 | $ 21,500,000 | $ 0
Business acquisition, transaction costs |  | $ 76,000 | $ 78,000 | 118,000 | 781,000 | 900,000 | 900,000 | 1,400,000
Impairment losses of real property assets recognized |  |  |  | 0 | 0 | 0 | 0 | 0
Indefinite lived trademark |  | 15,805,882 |  | 15,805,882 |  | 15,911,765 | 16,052,941 |
Allowance for doubtful accounts |  | 900,000 |  | 900,000 |  | 700,000 | 500,000 |
Gross amounts of lease intangibles |  | 80,500,000 |  | 80,500,000 |  | 88,500,000 | 68,600,000 |
Accumulated amortization |  | 78,300,000 |  | $ 78,300,000 |  | $ 72,900,000 | 56,800,000 |
Maximum annual contributions per employee, percentage |  |  |  | 100.00% |  | 100.00% |  |
Gains (losses) on exchange rate changes in equity investments recorded in other income (expense) |  | 3,800,000 | (8,700,000) | $ 700,000 | (11,100,000) | $ 9,600,000 | 3,800,000 |
Redemptions of common stock |  |  |  |  |  | $ 2,400,000 | $ 5,600,000 | $ 2,000,000
Redemptions of common stock (in shares) | shares |  |  |  |  |  | 0.2 | 0.4 | 0.2
Employer matching contributions, amount |  | 100,000 | 100,000 | $ 400,000 | $ 400,000 | $ 500,000 | $ 200,000 |
Employer matching contribution, percent |  |  |  | 100.00% |  | 100.00% |  |
Employer matching contribution, percent of match |  |  |  |  | 4.00% | 4.00% |  |
Minimum percentage of ordinary taxable income to be distributed to stockholders |  |  |  | 90.00% |  | 90.00% |  |
Number of reportable business segments | Segment |  |  |  | 2 |  | 2 |  |
Finite-Lived Intangible Assets, Net, Total |  | $ 2,214,891 |  | $ 2,214,891 |  | $ 15,553,303 | $ 14,337,820 |
Investment, Type [Extensible Enumeration] |  | Real Estate Investment [Member] |  | Real Estate Investment [Member] |  | Real Estate Investment [Member] |  |
Rental Income | Geographic Concentration Risk | Florida |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Concentration Risk Percentage1 |  |  |  | 22.80% |  | 23.00% |  |
Rental Income | Geographic Concentration Risk | California |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Concentration Risk Percentage1 |  |  |  | 20.00% |  | 20.10% |  |
Rental Income | Geographic Concentration Risk | Greater Toronto Area of Canada |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Concentration Risk Percentage1 |  |  |  | 10.30% |  | 9.80% |  |
Class T Common stock |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Monthly stockholder servicing fee accrual description |  |  |  | accrued daily in an amount equal to 1/365th of 1% of the purchase price per share |  | accrued daily in an amount equal to 1/365th of 1% of the purchase price per share | accrues daily in an amount equal to 1/365th of 1% of the purchase price per share |
Redeemable Common Stock |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Redemptions of common stock |  |  |  |  |  |  | $ 1,700,000 | $ 700,000
Redeemable Common Stock | Share Redemption Program |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Redemptions of common stock |  |  |  |  |  |  | 3,900,000 | $ 1,300,000
Revolving Credit Facility |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Debt issuance cost, gross |  | $ 4,500,000 |  | $ 4,500,000 |  | $ 4,500,000 | 4,100,000 |
Accumulated amortization of debt issuance costs |  | 3,700,000 |  | 3,700,000 |  | 2,400,000 | 800,000 |
Non Revolving Debt |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Debt issuance cost, gross |  | 6,800,000 |  | 6,800,000 |  | 7,000,000 | 5,800,000 |
Accumulated amortization of debt issuance costs |  | 3,100,000 |  | 3,100,000 |  | 2,500,000 | 1,900,000 |
Self Storage |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Total estimated future amortization expense of intangible assets, year 2023 |  | 1,100,000 |  | 1,100,000 |  | 6,400,000 |  |
Total estimated future amortization expense of intangible assets, year 2024 |  | 100,000 |  | 100,000 |  | 100,000 |  |
Total estimated future amortization expense of intangible assets, year 2025 |  | 100,000 |  | 100,000 |  | 100,000 |  |
Total estimated future amortization expense of intangible assets, year 2026 |  | 100,000 |  | 100,000 |  | 100,000 |  |
Total estimated future amortization expense of intangible assets, thereafter |  |  |  |  |  | $ 800,000 |  |
Total estimated future amortization expense of intangible assets, year 2027 |  | 100,000 |  | 100,000 |  |  |  |
Total estimated future amortization expense of intangible assets, thereafter |  | 700,000 |  | 700,000 |  |  |  |
Finite-Lived Intangible Assets, Net, Total |  | 2,100,000 |  | $ 2,100,000 |  |  |  |
Weighted-average amortization period on remaining intangible assets |  |  |  | 3 years 2 months 12 days |  |  |  |
Minimum |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Estimated useful life |  |  |  | 3 years |  | 3 years |  |
Maximum |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Estimated useful life |  |  |  | 5 years |  | 5 years |  |
Strategic Storage Trademark |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Trademarks acquired amount |  | 105,000 |  | $ 105,000 |  | $ 211,000 | 400,000 |
Indefinite lived trademark |  | 15,700,000 |  | 15,700,000 |  | 15,700,000 | 15,700,000 |
Total estimated future amortization expense of intangible assets, year 2023 |  | 35,000 |  | 35,000 |  | 140,000 |  |
Total estimated future amortization expense of intangible assets, year 2024 |  | 70,000 |  | 70,000 |  | 70,000 |  |
Finite Lived Intangible Assets Amortization Expense After Year Two |  | 0 |  | $ 0 |  | $ 0 |  |
Self Administration Transaction |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Number of trademarks acquired | Trademark |  |  |  | 2 |  | 2 |  |
Total estimated future amortization expense of intangible assets, year 2023 |  |  |  |  |  | $ 55,000 |  |
Total estimated future amortization expense of intangible assets, year 2024 |  |  |  |  |  | 55,000 |  |
Total estimated future amortization expense of intangible assets, year 2025 |  |  |  |  |  | 0 |  |
Gross amounts of lease intangibles |  |  |  |  |  | 9,900,000 | 6,800,000 |
Accumulated amortization |  |  |  |  |  | 1,800,000 | 4,300,000 |
Pacific Oak Holding Group |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Variable interest entity non-voting ownership percentage | 10.00% |  |  |  |  |  |  |
Operating Expense |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Advertising costs |  | 1,200,000 | 1,200,000 | $ 3,600,000 | $ 3,300,000 | 4,400,000 | 3,700,000 |
General and Administrative Expense |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |  |  |  |
Advertising costs |  | $ 500,000 | $ 400,000 | $ 1,600,000 | $ 800,000 | $ 1,300,000 | $ 700,000 |

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