SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
Dec. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements are presented on the accrual basis of accounting in accordance with U.S. generally accepted accounting principles ("GAAP").
Principles of Consolidation and Noncontrolling Interests	Principles of Consolidation The Company's consolidated financial statements include the accounts of its operating partnership and its controlled subsidiaries. All significant intercompany balances and transactions have been eliminated in the consolidation of entities. When the Company obtains an economic interest in an entity, the Company evaluates the entity to determine if the entity is deemed a variable interest entity ("VIE"), and if the Company is deemed to be the primary beneficiary, in accordance with authoritative guidance issued on the consolidation of VIEs. When an entity is not deemed to be a VIE, the Company considers the provisions of additional guidance to determine whether the general partner controls a limited partnership or similar entity when the limited partners have certain rights. The Company consolidates all entities that are VIEs and of which the Company is deemed to be the primary beneficiary. The Company has determined that its operating partnership is a VIE. The sole significant asset of National Storage Affiliates Trust is its investment in its operating partnership, and consequently, substantially all of the Company's assets and liabilities represent those assets and liabilities of its operating partnership. As of December 31, 2024, the Company's operating partnership was the primary beneficiary of, and therefore consolidated, 22 DownREIT partnerships that are considered VIEs, which owned 49 self storage properties. The net book value of the real estate owned by these VIEs was $407.1 million and $418.9 million as of December 31, 2024 and December 31, 2023, respectively. For certain DownREIT partnerships which are subject to fixed rate mortgages payable, the carrying value of such fixed rate mortgages payable held by these VIEs was $172.9 million and $188.7 million as of December 31, 2024 and December 31, 2023, respectively. The creditors of the consolidated VIEs do not have recourse to the Company's general credit. Noncontrolling Interests All of the limited partner equity interests ("OP equity") in its operating partnership not held by the Company are reflected as noncontrolling interests. Noncontrolling interests also include ownership interests in DownREIT partnerships held by entities other than the Company's operating partnership. In the consolidated statements of operations, the Company allocates net income (loss) attributable to noncontrolling interests to arrive at net income (loss) attributable to National Storage Affiliates Trust. For transactions that result in changes to the Company's ownership interest in its operating partnership, the carrying amount of noncontrolling interests is adjusted to reflect such changes. The difference between the fair value of the consideration received or paid and the amount by which the noncontrolling interests is adjusted is reflected as an adjustment to additional paid-in capital on the consolidated balance sheets.
Self Storage Properties	Self Storage Properties Self storage properties are carried at historical cost less accumulated depreciation and any impairment losses. Major replacements and betterments, which improve or extend the life of an asset, are capitalized. Expenditures for ordinary repairs and maintenance are expensed as incurred and are included in property operating expenses. Estimated depreciable lives of self storage properties are determined by considering the age and other indicators about the condition of the assets at the respective dates of acquisition, resulting in a range of estimated useful lives for assets within each category. All self storage property assets are depreciated using the straight-line method. Buildings and improvements are depreciated over estimated useful lives primarily between seven and 40 years; furniture and equipment are depreciated over estimated useful lives primarily between three and 10 years. When a self storage property is acquired, the purchase price of the acquired self storage property is allocated to land, buildings and improvements, furniture and equipment, customer in-place leases, assumed real estate leasehold interests, and other assets acquired and liabilities assumed, based on the estimated fair value of each component. When a portfolio of self storage properties is acquired, the purchase price is allocated to the individual self storage properties based on the fair value determined using an income approach with appropriate risk-adjusted capitalization rates, which take into account the relative size, age and location of the individual self storage properties.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly-liquid investments purchased with original maturities of three months or less to be cash equivalents. From time to time, the Company maintains cash balances in financial institutions in excess of federally insured limits. The Company has never experienced a loss that resulted from exceeding federally insured limits.
Restricted Cash	Restricted Cash The Company's restricted cash consists of escrowed funds deposited with financial institutions resulting from property sales for which we elected to purchase replacement property in accordance with Section 1031 of the Code, and for real estate taxes, insurance and other reserves for capital improvements in accordance with the Company's loan agreements.
Customer In-place Leases	Customer In-place Leases In allocating the purchase price for a self storage property acquisition, the Company determines whether the acquisition includes intangible assets. The Company allocates a portion of the purchase price to an intangible asset attributed to the value of customer in-place leases. This intangible asset is amortized to expense using the straight-line method over 12 months, the estimated average rental period for the leases. Substantially all of the leases in place at acquired properties are at market rates, as the leases are month-to-month contracts.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company evaluates long-lived assets for impairment when events and circumstances indicate that there may be impairment. When events or changes in circumstances indicate that the Company's long-lived assets may not be recoverable, the carrying value of these long-lived assets is compared to the undiscounted future net operating cash flows, plus a terminal value attributable to the assets. If an asset's carrying value is not considered recoverable, an impairment loss is recorded to the extent the net carrying value of the asset exceeds the fair value.
Long Lived Assets Held for Sale	Long Lived Assets Held for Sale The Company considers long-lived assets to be “held for sale” upon satisfaction of the following criteria: (a) management commits to a plan to sell an asset (or group of assets), (b) the asset is available for immediate sale in its present condition subject only to terms that are usual and customary for sales of such assets, (c) an active program to locate a buyer and other actions required to complete the plan to sell the asset have been initiated, (d) the sale of the asset is probable and transfer of the asset is expected to be completed within one year, (e) the asset is being actively marketed for sale at a price that is reasonable in relation to its current fair value and (f) actions required to complete the plan indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn. Typically these criteria are all met when the relevant asset is under contract, significant non-refundable deposits have been made by the potential buyer, the assets are immediately available for transfer, and there are no contingencies related to the sale that may prevent the transaction from closing. However, each potential transaction is evaluated based on its separate facts and circumstances. Assets classified as held for sale are reported at the lesser of carrying value or fair value less estimated costs to sell and are not depreciated.
Costs of Raising Capital	Costs of Raising Capital Commissions, legal fees and other costs that are directly associated with equity offerings are capitalized as deferred offering costs, pending a determination of the success of the offering. Deferred offering costs related to successful offerings are charged to additional paid-in capital within equity in the period it is determined that the offering was successful.
Debt Issuance Costs	Debt issuance costs are amortized over the estimated life of the related debt using the straight-line method, which approximates the effective interest rate method. Amortization of debt issuance costs is included in interest expense in the accompanying consolidated statements of operations.
Revenue Recognition - Rental Revenue	Revenue Recognition Rental revenue Rental revenue consists of space rentals and related fees. Management has determined that all of the Company's leases are operating leases. Substantially all leases may be terminated on a month-to-month basis and rental income is recognized ratably over the lease term using the straight-line method. Rents received in advance are deferred and recognized on a straight-line basis over the related lease term associated with the prepayment. Promotional discounts and other incentives are recognized as a reduction to rental income over the applicable lease term.
Other Property-related Revenue and Management Fees and Other Revenue	Other property-related revenue Other property-related revenue primarily consists of ancillary revenues such as tenant insurance and/or tenant warranty protection-related access fees and sales of storage supplies which are recognized in the period earned. The Company has tenant insurance and/or tenant warranty protection plan-related arrangements with insurance companies and the Company’s tenants. During the years ended December 31, 2024, 2023 and 2022, the Company recognized $22.9 million, $24.1 million and $19.8 million, respectively, of tenant insurance and tenant warranty protection plan revenues. The Company sells boxes, packing supplies, locks and other retail merchandise at its properties. During the years ended December 31, 2024, 2023 and 2022, the Company recognized retail sales of $1.9 million, $2.3 million and $2.6 million, respectively. Management fees and other revenue Management fees and other revenue consist of property management fees, platform fees, call center fees, acquisition fees, amounts related to the facilitation of tenant warranty protection or tenant insurance programs for certain stores in the Company's consolidated portfolio and unconsolidated real estate ventures, access fees associated with tenant insurance-related arrangements, and profit distributions from the Company's interest in a reinsurance company. With respect to the 2016 Joint Venture, the 2018 Joint Venture, the 2023 Joint Venture and the 2024 Joint Venture (each as defined in Note 5), the Company provides supervisory and administrative property management services, centralized call center services, and technology platform and revenue management services to the properties in the unconsolidated real estate ventures. The property management fees for the 2016 Joint Venture, 2018 Joint Venture and 2023 Joint Venture are equal to 6% of monthly gross revenues and net sales revenues from the assets of the unconsolidated real estate ventures, and the platform fees are equal to $1,250 per month per unconsolidated real estate venture property. The property management fees for the 2024 Joint Venture are equal to 4% of monthly gross revenues and net sales revenues from the assets of the unconsolidated real estate venture. With respect to the 2016 Joint Venture, the 2023 Joint Venture and 2024 Joint Venture, the call center fee is equal to 1% of each of monthly gross revenues and net sales revenues. During the years ended December 31, 2024, 2023 and 2022, the Company recognized property management fees, call center fees and platform fees of $18.3 million, $16.8 million and $16.5 million, respectively. The Company also earns acquisition fees for properties acquired by the 2016 Joint Venture, the 2018 Joint Venture, 2023 Joint Venture and the 2024 Joint Venture. These fees are based on a percentage of the gross capitalization of the acquired assets determined by the members of the 2016 Joint Venture, the 2018 Joint Venture, the 2023 Joint Venture and the 2024 Joint Venture, and are generally earned when the unconsolidated real estate ventures obtain title and control of an acquired property. During the years ended December 31, 2024, 2023 and 2022, the Company recognized acquisition fees of $0.6 million, $0 and $1.2 million, respectively. The Company provides or makes available tenant insurance or tenant warranty protection programs for tenants at its properties. For certain of the properties in the Company’s consolidated portfolio and unconsolidated real estate ventures, the Company provides such tenant insurance through the Company’s wholly-owned captive insurance company and a separate reinsurance company in which the Company has a partial ownership interest. With respect to properties in the Company’s unconsolidated real estate ventures, the Company receives 50% of all proceeds from tenant insurance and tenant warranty protection programs at each unconsolidated real estate venture property in exchange for facilitating the programs at those properties. During the years ended December 31, 2024, 2023 and 2022, the Company recognized $22.8 million, $17.2 million and $9.5 million, respectively, of revenue related to these activities.
Advertising Costs	Advertising Costs The Company incurs advertising costs primarily attributable to internet, directory and other advertising. Advertising costs are included in property operating expenses in the accompanying consolidated statements of operations. These costs are expensed in the period in which the cost is incurred.
Acquisition Costs	Acquisition Costs The Company incurs title, legal and consulting fees, and other costs associated with the completion of acquisitions. The Company's self storage property acquisitions are accounted for as asset acquisitions, and accordingly, acquisition costs directly related to the self storage property acquisitions were capitalized as part of the basis of the acquired properties. Indirect acquisition costs remain included in acquisition costs in the accompanying consolidated statements of operations in the period in which they were incurred.
Income Taxes	Income Taxes The Company has elected and believes it has qualified to be taxed as a REIT under sections 856 through 860 of the U.S. Internal Revenue Code (the "Code") commencing with the taxable year ended December 31, 2015. To qualify as a REIT, among other things, the Company is required to distribute at least 90% of its REIT taxable income to its shareholders and meet certain tests regarding the nature of its income and assets. As a REIT, the Company is not subject to federal income tax on the earnings distributed currently to its shareholders that it derives from its REIT qualifying activities. If the Company fails to qualify as a REIT in any taxable year, and is unable to avail itself of certain provisions set forth in the Code, all of the Company's taxable income would be subject to federal and state income taxes at regular corporate rates. The Company will not be required to make distributions with respect to income derived from the activities conducted through subsidiaries that the Company elects to treat as taxable REIT subsidiaries ("TRS") for federal income tax purposes. Certain activities that the Company undertakes must be conducted by a TRS, such as performing non-customary services for its customers, facilitating sales of tenant insurance and holding assets that the Company is not permitted to hold directly. A TRS is subject to federal and state income taxes. On June 25, 2014, the Company formed NSA TRS, LLC ("NSA TRS"), a Delaware limited liability company. The Company has elected to treat NSA TRS as a TRS, and consequently, NSA TRS is subject to U.S. federal and state corporate income taxes. Deferred tax assets and liabilities are recognized to the extent of any differences between the financial reporting and tax bases of assets and liabilities. No material deferred tax assets and liabilities were recorded as of December 31, 2024 and 2023. The Company did not have any unrecognized tax benefits related to uncertain tax positions as of December 31, 2024 and 2023. Future amounts of accrued interest and penalties, if any, related to uncertain tax positions will be recorded as a component of income tax expense. The Company does not expect that the amount of unrecognized tax benefits will change significantly in the next 12 months. The Company's material taxing jurisdiction is the U.S. federal jurisdiction; the 2021 tax year is the earliest period that remains open to examination by these taxing jurisdictions.
Earnings per Share	Earnings per Share Basic earnings per share is calculated based on the weighted average number of the Company's common shares of beneficial interest, $0.01 par value per share ("common shares"), outstanding during the period. Diluted earnings per share is calculated by further adjusting for the dilutive impact using the treasury stock method for any share options and unvested share equivalents outstanding during the period and the if-converted method for any convertible securities outstanding during the period.
Equity-Based Awards	Equity-Based Awards The measurement and recognition of compensation cost for all equity-based awards granted to officers, trustees, employees and consultants is based on estimated fair values. Compensation cost is recognized on a straight-line basis over the requisite service periods of each award with non-graded vesting. For awards granted which contain a graded vesting schedule and the only condition for vesting is a service condition, compensation cost is recognized as an expense on a straight-line basis over the requisite service period as if the award was, in substance, a single award. For awards granted for which vesting is subject to a performance condition, compensation cost is recognized over the requisite service period if and when the Company concludes it is probable that the performance condition will be achieved. The estimated fair value of all equity-based awards issued to the Company's former PROs and their affiliates in connection with self storage property acquisitions is included in the cost of the respective acquisitions. The estimated fair value of such awards is measured at the date the self storage properties are acquired, as this date represents satisfaction of the performance condition and coincides with the award vesting.
Derivative Financial Instruments	Derivative Financial Instruments The Company carries all derivative financial instruments on the consolidated balance sheet at fair value. Fair value of derivatives is determined by reference to observable prices that are based on inputs not quoted on active markets, but corroborated by market data. The accounting for changes in the fair value of a derivative instrument depends on whether the derivative has been designated and qualifies as part of a hedging relationship. The Company's use of derivative instruments has been limited to interest rate swap and cap agreements. The fair values of derivative instruments are included in other assets and interest rate swap liabilities in the accompanying consolidated balance sheets. For derivative instruments not designated as cash flow hedges, the unrealized gains and losses are included in interest expense in the accompanying consolidated statements of operations. For derivatives designated as cash flow hedges, the effective portion of the changes in the fair value of the derivatives is initially reported in accumulated other comprehensive income (loss) in the Company's consolidated balance sheets and subsequently reclassified into earnings when the hedged transaction affects earnings. The valuation of interest rate swap and cap agreements is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves. The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash payments and the discounted expected variable cash receipts. The variable cash receipts are based on an expectation of future interest rates (forward curves) derived from observable market interest rate forward curves. The Company may enter into derivative contracts that are intended to economically hedge certain of its risk, even though hedge accounting does not apply or the Company elects not to apply hedge accounting.
Fair Value Measurements	Fair Value Measurements When measuring fair value of financial instruments that are required to be recorded or disclosed at fair value, the Company uses a three-tier measurement hierarchy which prioritizes the inputs used to calculate fair value. These tiers include Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions.
Investments in Unconsolidated Real Estate Venture	Investments in Unconsolidated Real Estate Ventures The Company’s investments in its unconsolidated real estate ventures are recorded under the equity method of accounting in the accompanying consolidated financial statements. Under the equity method, the Company’s investments in unconsolidated real estate ventures are stated at cost and adjusted for the Company’s share of net earnings or losses and reduced by distributions. Equity in earnings (losses) is recognized based on the Company’s ownership interest in the earnings (losses) of the unconsolidated real estate ventures. The Company follows the "nature of the distribution approach" for classification of distributions from its unconsolidated real estate ventures in its consolidated statements of cash flows. Under this approach, distributions are reported on the basis of the nature of the activity or activities that generated the distributions as either a return on investment, which are classified as operating cash flows, or a return of investment (e.g., proceeds from the unconsolidated real estate ventures' sale of assets) which are reported as investing cash flows.
Segment Reporting	Segment Reporting The Company manages its business as one reportable segment consisting of owning and managing self storage properties located in the United States. Although the Company operates in several markets, these operations have been aggregated into one reportable segment based on the similar economic characteristics among all markets, as discussed further in Note 15.
Allocation of Net Income (Loss)	Allocation of Net Income (Loss) Effective July 1, 2024, in connection with the Company's internalization of its PRO structure, all outstanding subordinated performance units of our operating partnership ("subordinated performance units'") including all units of the DownREIT partnerships intended to be economically equivalent to the subordinated performance units ("DownREIT subordinated performance units") were converted into OP units and DownREIT OP units, respectively. For periods in which the subordinated performance units were outstanding, the Company allocated GAAP income utilizing the HLBV method, in which income or loss was allocated based on the change in each unitholders’ claim on the net assets of its operating partnership at period end after adjusting for any distributions or contributions made during such period. For periods in which the subordinated performance units are not outstanding, the Company allocates GAAP income based on the number of common shares and partnership units (including DownREIT OP units) outstanding.
Other Comprehensive Income (Loss)	Other Comprehensive Income (Loss) The Company has cash flow hedge derivative instruments that are measured at fair value with unrealized gains or losses recognized in other comprehensive income (loss) with a corresponding adjustment to accumulated other comprehensive income (loss) within equity, as discussed further in Note 14.
Gain on sale of self storage properties	Gain on sale of self storage properties The Company recognizes gains from disposition of properties only upon closing in accordance with the guidance on sales of nonfinancial assets. Profit on real estate sold is recognized upon closing when all, or substantially all, of the promised consideration has been received and is nonrefundable and the Company has transferred control of the facilities to the purchaser.
Goodwill	Goodwill Goodwill represents the costs of business acquisitions in excess of the fair value of identifiable net assets acquired. The Company evaluates goodwill for potential impairment annually, or whenever impairment indicators are present.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Reclassifications	Reclassifications Certain amounts in the consolidated financial statements and related notes have been reclassified to conform to the current year presentation. Such reclassifications do not impact the Company's previously reported financial position or net income (loss). Internalization of PRO Structure The Company completed the internalization of its PRO structure on July 1, 2024 (the "Closing Date"). As a result of the internalization, the Company purchased certain of each PRO’s assets, which included each PRO’s asset management and property management contracts (collectively, the "management contracts"), certain of each PRO's intellectual property and brands ("PRO IP") and certain rights related to certain PROs' tenant insurance programs (collectively, along with the management contracts and PRO IP, the "PROs' intangible assets"). The Company is transitioning the majority of operations in a phased approach, which has begun and is expected to continue over the 12 month period following the Closing Date, and the Company has executed new asset management and property management agreements with a number of its former participating regional operators ("former PROs") for all or a part of this transitionary period at newly negotiated management fees. Consideration paid for the PROs' management contracts and PRO IP totaled approximately $34.6 million, consisting of 775,210 OP units and $3.4 million in cash. The Company allocated the purchase price to intangible assets acquired, consisting of management contracts and certain PROs' trade names. The Company also acquired certain rights related to certain PROs' tenant insurance-related programs. The consideration paid for the rights associated with the tenant insurance-related programs was approximately $60.3 million, consisting of 773,656 OP units and $29.2 million in cash. In addition, the Company incurred $1.4 million in transaction costs related to the transactions. Additionally, in connection with the internalization of its PRO structure, effective July 1, 2024, all 11,906,167 outstanding subordinated performance units including all DownREIT subordinated performance units were converted into an aggregate of 17,984,787 OP units and DownREIT OP units. Each subordinated performance unit and DownREIT subordinated performance unit was converted into a number of OP units and DownREIT OP units determined by dividing the average cash available for distribution ("CAD") per unit on the series subordinated performance units and DownREIT subordinated performance units over a one-year period ending December 31, 2023, by 110% of the CAD per unit on the OP units determined over the same period. CAD per unit on the series subordinated performance units, DownREIT subordinated performance units, OP units and DownREIT OP units was determined by the Company based upon the application of the provisions of the LP Agreement applicable to the distributions of operating cash flow and capital transactions proceeds. Retirement of PRO Effective January 1, 2023, one of our PROs, Move It Self Storage and its controlled affiliates, retired as one of the Company's PROs. As a result of the retirement, on January 1, 2023, management of our properties in the Move It managed portfolio was transferred to the Company and the Move It brand name and related intellectual property was internalized by the Company, and the Company discontinued payment of any supervisory and administrative fees or reimbursements to Move It. During the year ended December 31, 2023, the Company paid $4.7 million in cash for Move It's rights to its asset management agreements, the Move It brand, and other intellectual property. The Company also acquired Move It's interest in a reinsurance company for approximately $12.2 million in cash. Additionally, in connection with Move It's retirement, 2,545,063 OP units were issued as a result of the non-voluntary conversion of 926,623 subordinated performance units.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In November 2023, the Financial Accounting Standards Board ("FASB") issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures ("ASU 2023-07"). ASU 2023-07 requires disclosure of significant segment expenses that are regularly provided to the chief operating decision maker ("CODM") and included within the segment measure of profit or loss, an amount and description of its composition for other segment items to reconcile to segment profit or loss, and the title and position of the entity’s CODM. ASU 2023-07 will be applied retrospectively and is effective for annual reporting periods in fiscal years beginning after December 15, 2023, and interim reporting periods in fiscal years beginning after December 31, 2024. We adopted this accounting standard for the year ended December 31, 2024. While the adoption has no impact on our financial statements, it has resulted in incremental disclosures within the footnotes to our consolidated financial statements (for additional information see Note 15. Segments). In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Topic 220-40): Disaggregation of Income Statement Expenses ("ASU 2024-03"). ASU 2024-03 requires that public business entities disclose additional information about specific expense categories in the notes to financial statements at interim and annual reporting periods. ASU 2024-03 will be applied retrospectively and is effective for annual reporting periods in fiscal years beginning after December 15, 2026 and interim reporting periods within fiscal years beginning after December 15, 2027. Pursuant to this ASU, we do not expect the adoption to have a material impact on our financial statements. However, the footnotes to our consolidated financial statements will include additional disclosures regarding certain specific expense categories.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

12 Months Ended

Dec. 31, 2024

The accompanying consolidated financial statements are presented on the accrual basis of accounting in accordance with U.S. generally accepted accounting principles ("GAAP").

Principles of Consolidation and Noncontrolling Interests

Principles of Consolidation

The Company's consolidated financial statements include the accounts of its operating partnership and its controlled subsidiaries. All significant intercompany balances and transactions have been eliminated in the consolidation of entities.

When the Company obtains an economic interest in an entity, the Company evaluates the entity to determine if the entity is deemed a variable interest entity ("VIE"), and if the Company is deemed to be the primary beneficiary, in accordance with authoritative guidance issued on the consolidation of VIEs. When an entity is not deemed to be a VIE, the Company considers the provisions of additional guidance to determine whether the general partner controls a limited partnership or similar entity when the limited partners have certain rights. The Company consolidates all entities that are VIEs and of which the Company is deemed to be the primary beneficiary. The Company has determined that its operating partnership is a VIE. The sole significant asset of National Storage Affiliates Trust is its investment in its operating partnership, and consequently, substantially all of the Company's assets and liabilities represent those assets and liabilities of its operating partnership.

As of December 31, 2024, the Company's operating partnership was the primary beneficiary of, and therefore consolidated, 22 DownREIT partnerships that are considered VIEs, which owned 49 self storage properties. The net book value of the real estate owned by these VIEs was $407.1 million and $418.9 million as of December 31, 2024 and December 31, 2023, respectively. For certain DownREIT partnerships which are subject to fixed rate mortgages payable, the carrying value of such fixed rate mortgages payable held by these VIEs was $172.9 million and $188.7 million as of December 31, 2024 and December 31, 2023, respectively. The creditors of the consolidated VIEs do not have recourse to the Company's general credit.

Noncontrolling Interests

All of the limited partner equity interests ("OP equity") in its operating partnership not held by the Company are reflected as noncontrolling interests. Noncontrolling interests also include ownership interests in DownREIT partnerships held by entities other than the Company's operating partnership. In the consolidated statements of operations, the Company allocates net income (loss) attributable to noncontrolling interests to arrive at net income (loss) attributable to National Storage Affiliates Trust.

For transactions that result in changes to the Company's ownership interest in its operating partnership, the carrying amount of noncontrolling interests is adjusted to reflect such changes. The difference between the fair value of the consideration received or paid and the amount by which the noncontrolling interests is adjusted is reflected as an adjustment to additional paid-in capital on the consolidated balance sheets.

Self Storage Properties

Self storage properties are carried at historical cost less accumulated depreciation and any impairment losses. Major replacements and betterments, which improve or extend the life of an asset, are capitalized. Expenditures for ordinary repairs and maintenance are expensed as incurred and are included in property operating expenses. Estimated depreciable lives of self storage properties are determined by considering the age and other indicators about the condition of the assets at the respective dates of acquisition, resulting in a range of estimated useful lives for assets within each category. All self storage property assets are depreciated using the straight-line method. Buildings and improvements are depreciated over estimated useful lives primarily between seven and 40 years; furniture and equipment are depreciated over estimated useful lives primarily between three and 10 years.

When a self storage property is acquired, the purchase price of the acquired self storage property is allocated to land, buildings and improvements, furniture and equipment, customer in-place leases, assumed real estate leasehold interests, and other assets acquired and liabilities assumed, based on the estimated fair value of each component. When a portfolio of self storage properties is acquired, the purchase price is allocated to the individual self storage properties based on the fair value determined using an income approach with appropriate risk-adjusted capitalization rates, which take into account the relative size, age and location of the individual self storage properties.

Cash and Cash Equivalents

The Company considers all highly-liquid investments purchased with original maturities of three months or less to be cash equivalents. From time to time, the Company maintains cash balances in financial institutions in excess of federally insured limits. The Company has never experienced a loss that resulted from exceeding federally insured limits.

Restricted Cash

The Company's restricted cash consists of escrowed funds deposited with financial institutions resulting from property sales for which we elected to purchase replacement property in accordance with Section 1031 of the Code, and for real estate taxes, insurance and other reserves for capital improvements in accordance with the Company's loan agreements.

Customer In-place Leases

In allocating the purchase price for a self storage property acquisition, the Company determines whether the acquisition includes intangible assets. The Company allocates a portion of the purchase price to an intangible asset attributed to the value of customer in-place leases. This intangible asset is amortized to expense using the straight-line method over 12 months, the estimated average rental period for the leases. Substantially all of the leases in place at acquired properties are at market rates, as the leases are month-to-month contracts.

Impairment of Long-Lived Assets

The Company evaluates long-lived assets for impairment when events and circumstances indicate that there may be impairment. When events or changes in circumstances indicate that the Company's long-lived assets may not be recoverable, the carrying value of these long-lived assets is compared to the undiscounted future net operating cash flows, plus a terminal value attributable to the assets. If an asset's carrying value is not considered recoverable, an impairment loss is recorded to the extent the net carrying value of the asset exceeds the fair value.

Long Lived Assets Held for Sale

The Company considers long-lived assets to be “held for sale” upon satisfaction of the following criteria: (a) management commits to a plan to sell an asset (or group of assets), (b) the asset is available for immediate sale in its present condition subject only to terms that are usual and customary for sales of such assets, (c) an active program to locate a buyer and other actions required to complete the plan to sell the asset have been initiated, (d) the sale of the asset is probable and transfer of the asset is expected to be completed within one year, (e) the asset is being actively marketed for sale at a price that is reasonable in relation to its current fair value and (f) actions required to complete the plan indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn.

Typically these criteria are all met when the relevant asset is under contract, significant non-refundable deposits have been made by the potential buyer, the assets are immediately available for transfer, and there are no contingencies related to the sale that may prevent the transaction from closing. However, each potential transaction is evaluated based on its separate facts and circumstances. Assets classified as held for sale are reported at the lesser of carrying value or fair value less estimated costs to sell and are not depreciated.

Costs of Raising Capital

Commissions, legal fees and other costs that are directly associated with equity offerings are capitalized as deferred offering costs, pending a determination of the success of the offering. Deferred offering costs related to successful offerings are charged to additional paid-in capital within equity in the period it is determined that the offering was successful.

Debt Issuance Costs

Debt issuance costs are amortized over the estimated life of the related debt using the straight-line method, which approximates the effective interest rate method. Amortization of debt issuance costs is included in interest expense in the accompanying consolidated statements of operations.

Revenue Recognition - Rental Revenue

Revenue Recognition

Rental revenue

Rental revenue consists of space rentals and related fees. Management has determined that all of the Company's leases are operating leases. Substantially all leases may be terminated on a month-to-month basis and rental income is recognized ratably over the lease term using the straight-line method. Rents received in advance are deferred and recognized on a straight-line basis over the related lease term associated with the prepayment. Promotional discounts and other incentives are recognized as a reduction to rental income over the applicable lease term.

Other Property-related Revenue and Management Fees and Other Revenue

Other property-related revenue

Other property-related revenue primarily consists of ancillary revenues such as tenant insurance and/or tenant warranty protection-related access fees and sales of storage supplies which are recognized in the period earned.

The Company has tenant insurance and/or tenant warranty protection plan-related arrangements with insurance companies and the Company’s tenants. During the years ended December 31, 2024, 2023 and 2022, the Company recognized $22.9 million, $24.1 million and $19.8 million, respectively, of tenant insurance and tenant warranty protection plan revenues.

The Company sells boxes, packing supplies, locks and other retail merchandise at its properties. During the years ended December 31, 2024, 2023 and 2022, the Company recognized retail sales of $1.9 million, $2.3 million and $2.6 million, respectively.

Management fees and other revenue

Management fees and other revenue consist of property management fees, platform fees, call center fees, acquisition fees, amounts related to the facilitation of tenant warranty protection or tenant insurance programs for certain stores in the Company's consolidated portfolio and unconsolidated real estate ventures, access fees associated with tenant insurance-related arrangements, and profit distributions from the Company's interest in a reinsurance company.

With respect to the 2016 Joint Venture, the 2018 Joint Venture, the 2023 Joint Venture and the 2024 Joint Venture (each as defined in Note 5), the Company provides supervisory and administrative property management services, centralized call center services, and technology platform and revenue management services to the properties in the unconsolidated real estate ventures. The property management fees for the 2016 Joint Venture, 2018 Joint Venture and 2023 Joint Venture are equal to 6% of monthly gross revenues and net sales revenues from the assets of the unconsolidated real estate ventures, and the platform fees are equal to $1,250 per month per unconsolidated real estate venture property. The property management fees for the 2024 Joint Venture are equal to 4% of monthly gross revenues and net sales revenues from the assets of the unconsolidated real estate venture. With respect to the 2016 Joint Venture, the 2023 Joint Venture and 2024 Joint Venture, the call center fee is equal to 1% of each of monthly gross revenues and net sales revenues. During the years ended December 31, 2024, 2023 and 2022, the Company recognized property management fees, call center fees and platform fees of $18.3 million, $16.8 million and $16.5 million, respectively.

The Company also earns acquisition fees for properties acquired by the 2016 Joint Venture, the 2018 Joint Venture, 2023 Joint Venture and the 2024 Joint Venture. These fees are based on a percentage of the gross capitalization of the acquired assets determined by the members of the 2016 Joint Venture, the 2018 Joint Venture, the 2023 Joint Venture and the 2024 Joint Venture, and are generally earned when the unconsolidated real estate ventures obtain title and control of an acquired property. During the years ended December 31, 2024, 2023 and 2022, the Company recognized acquisition fees of $0.6 million, $0 and $1.2 million, respectively.

The Company provides or makes available tenant insurance or tenant warranty protection programs for tenants at its properties. For certain of the properties in the Company’s consolidated portfolio and unconsolidated real estate ventures, the Company provides such tenant insurance through the Company’s wholly-owned captive insurance company and a separate reinsurance company in which the Company has a partial ownership interest. With respect to properties in the Company’s unconsolidated real estate ventures, the Company receives 50% of all proceeds from tenant insurance and tenant warranty protection programs at each unconsolidated real estate venture property in exchange for facilitating the programs at those properties. During the years ended December 31, 2024, 2023 and 2022, the Company recognized $22.8 million, $17.2 million and $9.5 million, respectively, of revenue related to these activities.

Advertising Costs

The Company incurs advertising costs primarily attributable to internet, directory and other advertising. Advertising costs are included in property operating expenses in the accompanying consolidated statements of operations. These costs are expensed in the period in which the cost is incurred.

Acquisition Costs

The Company incurs title, legal and consulting fees, and other costs associated with the completion of acquisitions. The Company's self storage property acquisitions are accounted for as asset acquisitions, and accordingly, acquisition costs directly related to the self storage property acquisitions were capitalized as part of the basis of the acquired properties. Indirect acquisition costs remain included in acquisition costs in the accompanying consolidated statements of operations in the period in which they were incurred.

Income Taxes

The Company has elected and believes it has qualified to be taxed as a REIT under sections 856 through 860 of the U.S. Internal Revenue Code (the "Code") commencing with the taxable year ended December 31, 2015. To qualify as a REIT, among other things, the Company is required to distribute at least 90% of its REIT taxable income to its shareholders and meet certain tests regarding the nature of its income and assets. As a REIT, the Company is not subject to federal income tax on the earnings distributed currently to its shareholders that it derives from its REIT qualifying activities. If the Company fails to qualify as a REIT in any taxable year, and is unable to avail itself of certain provisions set forth in the Code, all of the Company's taxable income would be subject to federal and state income taxes at regular corporate rates.

The Company will not be required to make distributions with respect to income derived from the activities conducted through subsidiaries that the Company elects to treat as taxable REIT subsidiaries ("TRS") for federal income tax purposes. Certain activities that the Company undertakes must be conducted by a TRS, such as performing non-customary services for its customers, facilitating sales of tenant insurance and holding assets that the Company is not permitted to hold directly. A TRS is subject to federal and state income taxes.

On June 25, 2014, the Company formed NSA TRS, LLC ("NSA TRS"), a Delaware limited liability company. The Company has elected to treat NSA TRS as a TRS, and consequently, NSA TRS is subject to U.S. federal and state corporate income taxes. Deferred tax assets and liabilities are recognized to the extent of any differences between the financial reporting and tax bases of assets and liabilities. No material deferred tax assets and liabilities were recorded as of December 31, 2024 and 2023.

The Company did not have any unrecognized tax benefits related to uncertain tax positions as of December 31, 2024 and 2023. Future amounts of accrued interest and penalties, if any, related to uncertain tax positions will be recorded as a component of income tax expense. The Company does not expect that the amount of unrecognized tax benefits will change significantly in the next 12 months.

The Company's material taxing jurisdiction is the U.S. federal jurisdiction; the 2021 tax year is the earliest period that remains open to examination by these taxing jurisdictions.

Earnings per Share

Basic earnings per share is calculated based on the weighted average number of the Company's common shares of beneficial interest, $0.01 par value per share ("common shares"), outstanding during the period. Diluted earnings per share is calculated by further adjusting for the dilutive impact using the treasury stock method for any share options and unvested share equivalents outstanding during the period and the if-converted method for any convertible securities outstanding during the period.

Equity-Based Awards

The measurement and recognition of compensation cost for all equity-based awards granted to officers, trustees, employees and consultants is based on estimated fair values. Compensation cost is recognized on a straight-line basis over the requisite service periods of each award with non-graded vesting. For awards granted which contain a graded vesting schedule and the only condition for vesting is a service condition, compensation cost is recognized as an expense on a straight-line basis over the requisite service period as if the award was, in substance, a single award. For awards granted for which vesting is subject to a performance condition, compensation cost is recognized over the requisite service period if and when the Company concludes it is probable that the performance condition will be achieved.

The estimated fair value of all equity-based awards issued to the Company's former PROs and their affiliates in connection with self storage property acquisitions is included in the cost of the respective acquisitions. The estimated fair value of such awards is measured at the date the self storage properties are acquired, as this date represents satisfaction of the performance condition and coincides with the award vesting.

Derivative Financial Instruments

The Company carries all derivative financial instruments on the consolidated balance sheet at fair value. Fair value of derivatives is determined by reference to observable prices that are based on inputs not quoted on active markets, but corroborated by market data. The accounting for changes in the fair value of a derivative instrument depends on whether the derivative has been designated and qualifies as part of a hedging relationship. The Company's use of derivative instruments has been limited to interest rate swap and cap agreements. The fair values of derivative instruments are included in other assets and interest rate swap liabilities in the accompanying consolidated balance sheets. For derivative instruments not designated as cash flow hedges, the unrealized gains and losses are included in interest expense in the accompanying consolidated statements of operations. For derivatives designated as cash flow hedges, the effective portion of the changes in the fair value of the derivatives is initially reported in accumulated other comprehensive income (loss) in the Company's consolidated balance sheets and subsequently reclassified into earnings when the hedged transaction affects earnings.

The valuation of interest rate swap and cap agreements is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves. The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash payments and the discounted expected variable cash receipts. The variable cash receipts are based on an expectation of future interest rates (forward curves) derived from observable market interest rate forward curves. The Company may enter into derivative contracts that are intended to economically hedge certain of its risk, even though hedge accounting does not apply or the Company elects not to apply hedge accounting.

Fair Value Measurements

When measuring fair value of financial instruments that are required to be recorded or disclosed at fair value, the Company uses a three-tier measurement hierarchy which prioritizes the inputs used to calculate fair value. These tiers include Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions.

Investments in Unconsolidated Real Estate Venture

Investments in Unconsolidated Real Estate Ventures

The Company’s investments in its unconsolidated real estate ventures are recorded under the equity method of accounting in the accompanying consolidated financial statements. Under the equity method, the Company’s investments in unconsolidated real estate ventures are stated at cost and adjusted for the Company’s share of net earnings or losses and reduced by distributions. Equity in earnings (losses) is recognized based on the Company’s ownership interest in the earnings (losses) of the unconsolidated real estate ventures. The Company follows the "nature of the distribution approach" for classification of distributions from its unconsolidated real estate ventures in its consolidated statements of cash flows. Under this approach, distributions are reported on the basis of the nature of the activity or activities that generated the distributions as either a return on investment, which are classified as operating cash flows, or a return of investment (e.g., proceeds from the unconsolidated real estate ventures' sale of assets) which are reported as investing cash flows.

Segment Reporting

The Company manages its business as one reportable segment consisting of owning and managing self storage properties located in the United States. Although the Company operates in several markets, these operations have been aggregated into one reportable segment based on the similar economic characteristics among all markets, as discussed further in Note 15.

Allocation of Net Income (Loss)

Effective July 1, 2024, in connection with the Company's internalization of its PRO structure, all outstanding subordinated performance units of our operating partnership ("subordinated performance units'") including all units of the DownREIT partnerships intended to be economically equivalent to the subordinated performance units ("DownREIT subordinated performance units") were converted into OP units and DownREIT OP units, respectively. For periods in which the subordinated performance units were outstanding, the Company allocated GAAP income utilizing the HLBV method, in which income or loss was allocated based on the change in each unitholders’ claim on the net assets of its operating partnership at period end after adjusting for any distributions or contributions made during such period. For periods in which the subordinated performance units are not outstanding, the Company allocates GAAP income based on the number of common shares and partnership units (including DownREIT OP units) outstanding.

Other Comprehensive Income (Loss)

The Company has cash flow hedge derivative instruments that are measured at fair value with unrealized gains or losses recognized in other comprehensive income (loss) with a corresponding adjustment to accumulated other comprehensive income (loss) within equity, as discussed further in Note 14.

Gain on sale of self storage properties

The Company recognizes gains from disposition of properties only upon closing in accordance with the guidance on sales of nonfinancial assets. Profit on real estate sold is recognized upon closing when all, or substantially all, of the promised consideration has been received and is nonrefundable and the Company has transferred control of the facilities to the purchaser.

Goodwill

Goodwill represents the costs of business acquisitions in excess of the fair value of identifiable net assets acquired. The Company evaluates goodwill for potential impairment annually, or whenever impairment indicators are present.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

Reclassifications

Certain amounts in the consolidated financial statements and related notes have been reclassified to conform to the current year presentation. Such reclassifications do not impact the Company's previously reported financial position or net income (loss).

Internalization of PRO Structure

The Company completed the internalization of its PRO structure on July 1, 2024 (the "Closing Date"). As a result of the internalization, the Company purchased certain of each PRO’s assets, which included each PRO’s asset management and property management contracts (collectively, the "management contracts"), certain of each PRO's intellectual property and brands ("PRO IP") and certain rights related to certain PROs' tenant insurance programs (collectively, along with the management contracts and PRO IP, the "PROs' intangible assets"). The Company is transitioning the majority of operations in a phased approach, which has begun and is expected to continue over the 12 month period following the Closing Date, and the Company has executed new asset management and property management agreements with a number of its former participating regional operators ("former PROs") for all or a part of this transitionary period at newly negotiated management fees.

Consideration paid for the PROs' management contracts and PRO IP totaled approximately $34.6 million, consisting of 775,210 OP units and $3.4 million in cash. The Company allocated the purchase price to intangible assets acquired, consisting of management contracts and certain PROs' trade names. The Company also acquired certain rights related to certain PROs' tenant insurance-related programs. The consideration paid for the rights associated with the tenant insurance-related programs was approximately $60.3 million, consisting of 773,656 OP units and $29.2 million in cash. In addition, the Company incurred $1.4 million in transaction costs related to the transactions.

Additionally, in connection with the internalization of its PRO structure, effective July 1, 2024, all 11,906,167 outstanding subordinated performance units including all DownREIT subordinated performance units were converted into an aggregate of 17,984,787 OP units and DownREIT OP units. Each subordinated performance unit and DownREIT subordinated performance unit was converted into a number of OP units and DownREIT OP units determined by dividing the average cash available for distribution ("CAD") per unit on the series subordinated performance units and DownREIT subordinated performance units over a one-year period ending December 31, 2023, by 110% of the CAD per unit on the OP units determined over the same period. CAD per unit on the series subordinated performance units, DownREIT subordinated performance units, OP units and DownREIT OP units was determined by the Company based upon the application of the provisions of the LP Agreement applicable to the distributions of operating cash flow and capital transactions proceeds.

Retirement of PRO

Effective January 1, 2023, one of our PROs, Move It Self Storage and its controlled affiliates, retired as one of the Company's PROs. As a result of the retirement, on January 1, 2023, management of our properties in the Move It managed portfolio was transferred to the Company and the Move It brand name and related intellectual property was internalized by the Company, and the Company discontinued payment of any supervisory and administrative fees or reimbursements to Move It.

During the year ended December 31, 2023, the Company paid $4.7 million in cash for Move It's rights to its asset management agreements, the Move It brand, and other intellectual property. The Company also acquired Move It's interest in a reinsurance company for approximately $12.2 million in cash. Additionally, in connection with Move It's retirement, 2,545,063 OP units were issued as a result of the non-voluntary conversion of 926,623 subordinated performance units.

Recently Issued Accounting Pronouncements

In November 2023, the Financial Accounting Standards Board ("FASB") issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures ("ASU 2023-07"). ASU 2023-07 requires disclosure of significant segment expenses that are regularly provided to the chief operating decision maker ("CODM") and included within the segment measure of profit or loss, an amount and description of its composition for other segment items to reconcile to segment profit or loss, and the title and position of the entity’s CODM. ASU 2023-07 will be applied retrospectively and is effective for annual reporting periods in fiscal years beginning after December 15, 2023, and interim reporting periods in fiscal years beginning after December 31, 2024. We adopted this accounting standard for the year ended December 31, 2024. While the adoption has no impact on our financial statements, it has resulted in incremental disclosures within the footnotes to our consolidated financial statements (for additional information see Note 15. Segments).

In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Topic 220-40): Disaggregation of Income Statement Expenses ("ASU 2024-03"). ASU 2024-03 requires that public business entities disclose additional information about specific expense categories in the notes to financial statements at interim and annual reporting periods. ASU 2024-03 will be applied retrospectively and is effective for annual reporting periods in fiscal years beginning after December 15, 2026 and interim reporting periods within fiscal years beginning after December 15, 2027. Pursuant to this ASU, we do not expect the adoption to have a material impact on our financial statements. However, the footnotes to our consolidated financial statements will include additional disclosures regarding certain specific expense categories.