| Document and Entity Information Document | May 01, 2024 |
| Entity Information [Line Items] | |
| Document Type | 8-K/A |
| Document Period End Date | May 01, 2024 |
| Entity Registrant Name | National Storage Affiliates Trust |
| Entity Central Index Key | 0001618563 |
| Amendment Flag | true |
| Entity Incorporation, State or Country Code | MD |
| Entity File Number | 001-37351 |
| Entity Tax Identification Number | 46-5053858 |
| Entity Address, Address Line One | 8400 East Prentice Avenue, 9th Floor |
| Entity Address, City or Town | Greenwood Village |
| Entity Address, State or Province | CO |
| Entity Address, Postal Zip Code | 80111 |
| City Area Code | 720 |
| Local Phone Number | 630-2600 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Amendment Description | This Current Report on Form 8-K/A (the “8-K/A”) amends the Original 8-K solely for the purpose of correcting a clerical error where same store rental revenue and net operating income for the three months ended September 30, 2023 in supplemental schedules 7 and 8 were inadvertently understated by $3.6 million leading to other related information for the same period and in the same schedules being similarly misreported. |
| Common Shares of Beneficial Interest, $0.01 par value per share [Member] | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Common Shares of Beneficial Interest, $0.01 par value per share |
| Trading Symbol | NSA |
| Security Exchange Name | NYSE |
| Series A Cumulative Redeemable Preferred Shares of Beneficial Interest, par value $0.01 per share [Member] | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Series A Cumulative Redeemable Preferred Shares of Beneficial Interest, par value $0.01 per share |
| Trading Symbol | NSA Pr A |
| Security Exchange Name | NYSE |
| Series B Preferred Stock | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Series B Cumulative Redeemable Preferred Shares of Beneficial Interest, par value $0.01 per share |
| Trading Symbol | NSA Pr B |
| Security Exchange Name | NYSE |
