ORGANIZATION AND NATURE OF OPERATIONS	3 Months Ended
Mar. 31, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ORGANIZATION AND NATURE OF OPERATIONS	ORGANIZATION AND NATURE OF OPERATIONS National Storage Affiliates Trust was organized in the state of Maryland on May 16, 2013 and is a fully integrated, self-administered and self-managed real estate investment trust focused on the self storage sector. As used herein, "NSA," the "Company," "we," "our," and "us" refers to National Storage Affiliates Trust and its consolidated subsidiaries, except where the context indicates otherwise. The Company has elected and believes that it has qualified to be taxed as a real estate investment trust for U.S. federal income tax purposes ("REIT") commencing with its taxable year ended December 31, 2015. Through its controlling interest as the sole general partner of NSA OP, LP (its "operating partnership"), a Delaware limited partnership formed on February 13, 2013, the Company is focused on the ownership, operation, and acquisition of self storage properties predominantly located within the top 100 metropolitan statistical areas in the United States. Pursuant to the operating partnership's Fourth Amended and Restated Agreement of Limited Partnership (the "LP Agreement"), the operating partnership is authorized to issue preferred units, Class A Units ("OP units") and Long-Term Incentive Plan Units ("LTIP units"). The Company also owns certain of its self storage properties through other consolidated subsidiaries of its operating partnership, which the Company refers to as "DownREIT partnerships." The DownREIT partnerships issue equity ownership interests that are intended to be economically equivalent to the Company's OP units ("DownREIT OP units"). The Company owned 799 consolidated self storage properties in 33 states and Puerto Rico with approximately 51.1 million rentable square feet in approximately 402,000 storage units as of March 31, 2026, excluding three properties classified as held for sale that were sold to a third party in April 2026. As of March 31, 2026, the Company also managed through its property management platform an additional portfolio of 262 properties owned by the Company's unconsolidated real estate ventures. These properties contain approximately 18.2 million rentable square feet, configured in approximately 145,000 storage units and located across 24 states. The Company owns a 25% equity interest in each of its unconsolidated real estate ventures. As of March 31, 2026, the Company operated and held ownership interests in 1,061 self storage properties located across 37 states and Puerto Rico with approximately 69.3 million rentable square feet in approximately 547,000 storage units. Merger Agreement On March 16, 2026, the Company and Public Storage, a Maryland real estate investment trust ("Public Storage"), entered into an Agreement and Plan of Merger (the "Merger Agreement"), by and among the Company, its operating partnership, Public Storage, Public Storage OP, L.P., a Delaware limited partnership ("Public Storage OP"), Pelican Merger Sub I, LLC, a Delaware limited liability company ("Merger Sub I"), and Pelican Merger Sub II, LLC, a Delaware limited liability company ("Merger Sub II"). Pursuant to the terms and subject to the conditions set forth in the Merger Agreement, and among other things, (i) the Company will merge with and into Merger Sub I, with Merger Sub I continuing as the surviving company (the "Company Merger"), and (ii) Merger Sub II will merge with and into the Operating Partnership, with the Operating Partnership continuing as the surviving partnership and as a wholly owned subsidiary of Public Storage Operating Company, a Maryland real estate investment trust (the "Partnership Merger" and together with the Company Merger, the "Mergers"). In connection with the Mergers, (i) each outstanding common share of the Company will be automatically converted into the right to receive 0.1400 (the "exchange ratio") common shares of Public Storage, (ii) each outstanding preferred share of the Company will be automatically converted into the right to receive one preferred share of Public Storage having rights, preferences, privileges and voting powers that are materially unchanged from the rights, preferences, privileges and voting powers of the corresponding class or series of preferred shares of the Company, (iii) each outstanding OP unit will be automatically converted into 0.1400 operating partnership units of Public Storage OP, (iv) each outstanding Series A-1 Cumulative Redeemable Preferred Unit ("Series A-1 preferred unit") of the operating partnership will be automatically converted into one new validly issued preferred unit of Public Storage OP, and (v) with respect to LTIP Units, 2026 performance-vesting LTIP Units will be canceled for no consideration, and each other unvested LTIP Unit will vest in full (with performance conditions deemed achieved at target) and be converted into one unit of Public Storage OP. Immediately prior to closing, the Company and certain limited partners of the operating partnership will form a joint venture (the "Dropdown JV") consisting of 313 properties. The Mergers are expected to close in the third quarter of 2026, subject to the approval of the Company’s equity holders and the satisfaction of other customary closing conditions.

National Storage Affiliates Trust was organized in the state of Maryland on May 16, 2013 and is a fully integrated, self-administered and self-managed real estate investment trust focused on the self storage sector. As used herein, "NSA," the "Company," "we," "our," and "us" refers to National Storage Affiliates Trust and its consolidated subsidiaries, except where the context indicates otherwise. The Company has elected and believes that it has qualified to be taxed as a real estate investment trust for U.S. federal income tax purposes ("REIT") commencing with its taxable year ended December 31, 2015.

Through its controlling interest as the sole general partner of NSA OP, LP (its "operating partnership"), a Delaware limited partnership formed on February 13, 2013, the Company is focused on the ownership, operation, and acquisition of self storage properties predominantly located within the top 100 metropolitan statistical areas in the United States. Pursuant to the operating partnership's Fourth Amended and Restated Agreement of Limited Partnership (the "LP Agreement"), the operating partnership is authorized to issue preferred units, Class A Units ("OP units") and Long-Term Incentive Plan Units ("LTIP units"). The Company also owns certain of its self storage properties through other consolidated subsidiaries of its operating partnership, which the Company refers to as "DownREIT partnerships." The DownREIT partnerships issue equity ownership interests that are intended to be economically equivalent to the Company's OP units ("DownREIT OP units").

On March 16, 2026, the Company and Public Storage, a Maryland real estate investment trust ("Public Storage"), entered into an Agreement and Plan of Merger (the "Merger Agreement"), by and among the Company, its operating partnership, Public Storage, Public Storage OP, L.P., a Delaware limited partnership ("Public Storage OP"), Pelican Merger Sub I, LLC, a Delaware limited liability company ("Merger Sub I"), and Pelican Merger Sub II, LLC, a Delaware limited liability company ("Merger Sub II"). Pursuant to the terms and subject to the conditions set forth in the Merger Agreement, and among other things, (i) the Company will merge with and into Merger Sub I, with Merger Sub I continuing as the surviving company (the "Company Merger"), and (ii) Merger Sub II will merge with and into the Operating Partnership, with the Operating Partnership continuing as the surviving partnership and as a wholly owned subsidiary of Public Storage Operating Company, a Maryland real estate investment trust (the "Partnership Merger" and together with the Company Merger, the "Mergers"). In connection with the Mergers, (i) each outstanding common share of the Company will be automatically converted into the right to receive 0.1400 (the "exchange ratio") common shares of Public Storage, (ii) each outstanding preferred share of the Company will be automatically converted into the right to receive one preferred share of Public Storage having rights, preferences, privileges and voting powers that are materially unchanged from the rights, preferences, privileges and voting powers of the corresponding class or series of preferred shares of the Company, (iii) each outstanding OP unit will be automatically converted into 0.1400 operating partnership units of Public Storage OP, (iv) each outstanding Series A-1 Cumulative Redeemable Preferred Unit ("Series A-1 preferred unit") of the operating partnership will be automatically converted into one new validly issued preferred unit of Public Storage OP, and (v) with respect to LTIP Units, 2026 performance-vesting LTIP Units will be canceled for no consideration, and each other unvested LTIP Unit will vest in full (with performance conditions deemed achieved at target) and be converted into one unit of Public Storage OP. Immediately prior to closing, the Company and certain limited partners of the operating partnership will form a joint venture (the "Dropdown JV") consisting of 313 properties. The Mergers are expected to close in the third quarter of 2026, subject to the approval of the Company’s equity holders and the satisfaction of other customary closing conditions.