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INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Narrative (Details) ft² in Thousands, $ in Thousands |  |  | 3 Months Ended | 9 Months Ended |  |
--- | --- | --- | --- | --- | --- | ---
Feb. 13, 2024 USD ($) | Dec. 15, 2023 USD ($) extension_period | Sep. 30, 2024 USD ($) ft² state property storage_unit | Sep. 30, 2025 USD ($) ft² state property storage_unit | Dec. 31, 2024 USD ($) | Feb. 29, 2024 ft² state storage_unit property
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Number of self storage properties | property |  |  |  | 1,069 |  |
Number of states in which self storage properties are located | state |  |  |  | 37 |  |
Total rentable square feet in self storage properties | ft² |  |  |  | 69,800 |  |
Investment in unconsolidated real estate ventures | $ |  |  |  | $ 235,385 | $ 246,193 |
Number of units in real estate property | storage_unit |  |  |  | 551,000 |  |
Joint Venture | Unconsolidated properties |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Number of self storage properties | property |  |  |  | 262 |  |
Number of states in which self storage properties are located | state |  |  |  | 24 |  |
Total rentable square feet in self storage properties | ft² |  |  |  | 18,200 |  |
Number of units in real estate property | storage_unit |  |  |  | 145,000 |  |
Joint Venture | Unconsolidated properties | 2023 Joint Venture |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Number of self storage properties | property |  |  | 18 | 3 |  |
Number of states in which self storage properties are located | state |  |  | 2 |  |  |
Total rentable square feet in self storage properties | ft² |  |  | 1,200 | 214 |  |
Number of units in real estate property | storage_unit |  |  | 8,000 | 1,600 |  |
2024 Joint Venture |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Real estate investments, joint ventures | $ | $ 210,000 |  |  |  |  |
Company's equity interest in unconsolidated real estate ventures (as a percent) | 6.05% |  |  |  |  |
Real estate investments, joint ventures, term | 5 years |  |  |  |  |
2024 Joint Venture | Joint Venture |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Real estate investments, joint ventures | $ | $ 140,800 |  |  |  |  |
2024 Joint Venture | Joint Venture | Unconsolidated properties |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Number of self storage properties | property |  |  |  | 56 |  | 56
Number of states in which self storage properties are located | state |  |  |  | 7 |  | 7
Total rentable square feet in self storage properties | ft² |  |  |  | 3,200 |  | 3,200
Number of storage units | storage_unit |  |  |  | 24,000 |  | 24,000
2024 Joint Venture | 2024 NSA Member |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Real estate investments, joint ventures | $ | $ 35,200 |  |  |  |  |
Company's equity interest in unconsolidated real estate ventures (as a percent) | 25.00% |  |  |  |  |
2024 Joint Venture | 2024 JV Investor |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Real estate investments, joint ventures | $ | $ 105,600 |  |  |  |  |
Company's equity interest in unconsolidated real estate ventures (as a percent) | 75.00% |  |  |  |  |
2023 Joint Venture |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Real estate investments, joint ventures | $ |  |  | $ 37,000 | $ 12,500 |  |
Real estate investments, joint ventures, term |  | 24 months |  |  |  |
Number of extension periods | extension_period |  | 2 |  |  |  |
Extension period |  | 6 months |  |  |  |
Payments to acquire interest in joint venture | $ |  |  | $ 147,900 | $ 50,000 |  |
2023 Joint Venture | Joint Venture | Unconsolidated properties |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Number of self storage properties | property |  |  |  | 21 |  |
Number of states in which self storage properties are located | state |  |  |  | 5 |  |
Total rentable square feet in self storage properties | ft² |  |  |  | 1,400 |  |
Number of units in real estate property | storage_unit |  |  |  | 9,000 |  |
2023 Joint Venture | 2023 JV Members |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Company's equity interest in unconsolidated real estate ventures (as a percent) |  | 75.00% |  |  |  |
Investment in unconsolidated real estate ventures | $ |  | $ 400,000 |  |  |  |
2023 Joint Venture | 2023 NSA Member |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Company's equity interest in unconsolidated real estate ventures (as a percent) |  | 25.00% |  |  |  |
2018 Joint Venture | Unconsolidated properties |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Company's equity interest in unconsolidated real estate ventures (as a percent) |  |  |  | 25.00% |  |
2018 Joint Venture | Joint Venture | Unconsolidated properties |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Company's equity interest in unconsolidated real estate ventures (as a percent) |  |  |  | 25.00% |  |
Number of self storage properties | property |  |  |  | 104 |  |
Number of states in which self storage properties are located | state |  |  |  | 17 |  |
Total rentable square feet in self storage properties | ft² |  |  |  | 7,900 |  |
Number of units in real estate property | storage_unit |  |  |  | 65,000 |  |
2016 Joint Venture | Unconsolidated properties |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Company's equity interest in unconsolidated real estate ventures (as a percent) |  |  |  | 25.00% |  |
2016 Joint Venture | Joint Venture | Unconsolidated properties |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |
Company's equity interest in unconsolidated real estate ventures (as a percent) |  |  |  | 25.00% |  |
Number of self storage properties | property |  |  |  | 81 |  |
Number of states in which self storage properties are located | state |  |  |  | 13 |  |
Total rentable square feet in self storage properties | ft² |  |  |  | 5,700 |  |
Number of units in real estate property | property |  |  |  | 47,000 |  |

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