EARNINGS PER SHARE - Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Numerator
Net income	$ 95,088	$ 40,392
Net income attributable to noncontrolling interests	(36,061)	(11,433)
Net income attributable to National Storage Affiliates Trust	59,027	28,959
Distributions to preferred shareholders	(5,110)	(3,962)
Distributed and undistributed earnings allocated to participating securities	(13)	(17)
Net income attributable to common shareholders - basic	53,904	24,980
Effect of assumed conversion of dilutive securities	35,218	11,305
Net income attributable to common shareholders - diluted	$ 89,122	$ 36,285
Denominator
Weighted average shares outstanding - basic (in shares)	80,236	89,499
Effect of dilutive securities:
Weighted average OP units outstanding (in shares)	37,633	38,736
Weighted average DownREIT OP unit equivalents outstanding (in shares)	2,120	2,120
Weighted average LTIP units outstanding (in shares)	128	76
Weighted average subordinated performance units and DownREIT subordinated performance unit equivalents (in shares)	18,031	18,191
Weighted average shares outstanding - diluted (in shares)	138,148	148,622
Earnings per share - basic (in dollars per share)	$ 0.67	$ 0.28
Earnings per share - diluted (in dollars per share)	$ 0.65	$ 0.24