INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Condensed Operating Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Related Party Transaction [Line Items]
Total revenue	$ 196,148	$ 207,993
Property operating expenses	(54,694)	(56,483)
Depreciation and amortization	(47,331)	(55,458)
Interest expense	(38,117)	(37,948)
Net income attributable to National Storage Affiliates Trust	59,027	28,959
Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Related Party Transaction [Line Items]
Total revenue	56,096	53,752
Property operating expenses	(17,603)	(15,049)
Supervisory, administrative and other expenses	(3,658)	(3,529)
Depreciation and amortization	(18,206)	(17,883)
Interest expense	(12,100)	(10,411)
Acquisition and other expenses	(59)	(232)
Net income attributable to National Storage Affiliates Trust	$ 4,470	$ 6,648