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SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS - Schedule of Units Reflecting Noncontrolling Interests (Details) - shares | Sep. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Partnership Subsidiaries |  |
Noncontrolling Interest [Line Items] |  |
Outstanding equity interest (in shares) | 59,443,787 | 59,940,227
Series A-1 preferred units | NSA OP, LP |  |
Noncontrolling Interest [Line Items] |  |
Outstanding equity interest (in shares) | 1,193,211 | 1,202,598
OP units | NSA OP, LP |  |
Noncontrolling Interest [Line Items] |  |
Outstanding equity interest (in shares) | 51,630,699 | 52,173,489
OP units | DownREIT Partnership |  |
Noncontrolling Interest [Line Items] |  |
Outstanding equity interest (in shares) | 5,769,214 | 5,769,214
LTIP units | NSA OP, LP |  |
Noncontrolling Interest [Line Items] |  |
Outstanding equity interest (in shares) | 850,663 | 794,926

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- Definition The number of limited partner units outstanding. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 5 -Subparagraph (SAB Topic 4.F) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480008/505-10-S99-5 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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