INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Condensed Operating Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Total reportable segment revenue	$ 770,335	$ 858,063	$ 801,569
Property operating expenses	(211,852)	(228,986)	(211,025)
Depreciation and amortization	(189,855)	(221,993)	(233,158)
Acquisition and other expenses	(3,616)	(1,659)	(2,745)
Net income attributable to National Storage Affiliates Trust	111,518	156,669	103,737
Equity Method Investment, Nonconsolidated Investee or Group of Investees | Joint Venture
Schedule of Equity Method Investments [Line Items]
Total reportable segment revenue	242,480	214,292	212,832
Property operating expenses	(76,558)	(59,740)	(57,306)
Supervisory, administrative and other expenses	(15,822)	(14,146)	(13,955)
Depreciation and amortization	(82,878)	(68,333)	(68,289)
Interest expense	(53,063)	(41,665)	(41,657)
Acquisition and other expenses	(677)	(459)	(899)
Net income attributable to National Storage Affiliates Trust	$ 13,482	$ 29,949	$ 30,726