EARNINGS PER SHARE - Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Numerator
Net income	$ 32,280	$ 95,088	$ 45,476	$ 40,392	$ 127,368	$ 85,868
Net income attributable to noncontrolling interests	(15,218)		(16,028)		(51,279)	(27,461)
Net income attributable to National Storage Affiliates Trust	17,062		29,448		76,089	58,407
Distributions to preferred shareholders	(5,110)		(5,119)		(10,220)	(8,799)
Distributed and undistributed earnings allocated to participating securities	(11)		(13)		(24)	(31)
Net income attributable to common shareholders - basic	11,941		24,316		65,845	49,577
Net income attributable to common shareholders - diluted	$ 11,941		$ 24,316		$ 65,845	$ 49,577
Denominator
Weighted average shares outstanding - basic (in shares)	75,160		88,312		77,698	88,902
Weighted average shares outstanding - diluted (in shares)	75,160		88,312		77,698	88,902
Earnings per share - basic (in dollars per share)	$ 0.16		$ 0.28		$ 0.85	$ 0.56
Earnings per share - diluted (in dollars per share)	$ 0.16		$ 0.28		$ 0.85	$ 0.56