National Storage Affiliates Trust Quarterly report pursuant to Section 13 or 15(d)

INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Narrative (Details) storage_unit in Thousands, ft² in Millions	Mar. 31, 2023 ft² storage_unit state property	Jan. 01, 2023 property
Schedule of Equity Method Investments [Line Items]
Number of self storage properties	1,117
Rentable square feet in self storage properties \| ft²	72.8
Number of storage units \| storage_unit	572
Number of states in which self storage properties are located \| state	42
Joint venture
Schedule of Equity Method Investments [Line Items]
Number of self storage properties		72
Unconsolidated properties \| Joint venture
Schedule of Equity Method Investments [Line Items]
Number of self storage properties	185
Rentable square feet in self storage properties \| ft²	13.5
Number of storage units \| storage_unit	111
Number of states in which self storage properties are located \| state	21
Unconsolidated properties \| Joint venture \| 2018 Joint Venture
Schedule of Equity Method Investments [Line Items]
Number of self storage properties	104
Rentable square feet in self storage properties \| ft²	7.8
Number of storage units \| storage_unit	64
Number of states in which self storage properties are located \| state	17
Unconsolidated properties \| Joint venture \| 2016 Joint Venture
Schedule of Equity Method Investments [Line Items]
Number of self storage properties	81
Rentable square feet in self storage properties \| ft²	5.6
Number of storage units \| storage_unit	47
Number of states in which self storage properties are located \| state	13