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, 2022 ft² storage_unit property state
Schedule of Equity Method Investments [Line Items]
Number of self storage properties \| property	1,061
Rentable square feet in self storage properties \| ft²	68.4
Number of storage units \| storage_unit	537
Number of states in which self storage properties are located \| state	42
Unconsolidated properties \| Joint venture \| 2018 Joint Venture
Schedule of Equity Method Investments [Line Items]
Number of self storage properties \| property	103
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 \| property	74
Rentable square feet in self storage properties \| ft²	4.9
Number of storage units \| storage_unit	40
Number of states in which self storage properties are located \| state	13