EARNINGS PER SHARE - Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Numerator
Net income	$ 183,270	$ 236,988	$ 183,765
Net income attributable to noncontrolling interests	(71,752)	(80,319)	(80,028)
Net income attributable to National Storage Affiliates Trust	111,518	156,669	103,737
Distributions to preferred shareholders	(20,445)	(19,019)	(13,425)
Distributed and undistributed earnings allocated to participating securities	(45)	(57)	(58)
Net income attributable to common shareholders - basic	91,028	137,593	90,254
Effect of assumed conversion of dilutive securities	0	78,196	0
Net income attributable to common shareholders - diluted	$ 91,028	$ 215,789	$ 90,254
Denominator
Weighted average shares outstanding - basic (in shares)	76,844	86,846	91,239
Effect of dilutive securities:
Weighted average OP units outstanding (in shares)	0	38,302	0
Weighted average DownREIT OP unit equivalents outstanding (in shares)	0	2,120	0
Weighted average LTIP units outstanding (in shares)	0	60	0
Weighted average subordinated performance units and DownREIT Subordinated performance unit equivalents (in shares)	0	18,695	0
Weighted average shares outstanding - diluted (in shares)	76,844	146,023	91,239
Earnings per share - basic (in dollars per share)	$ 1.18	$ 1.58	$ 0.99
Earnings per share - diluted (in dollars per share)	1.18	1.48	0.99
Dividends declared per common share (in dollars per share)	$ 2.25	$ 2.23	$ 2.15