National Storage Affiliates Trust Annual report pursuant to Section 13 and 15(d)

FAIR VALUE MEASUREMENTS - Interest Swap Derivatives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Interest Rate Swaps Measured at Fair Value
Losses on interest rate swaps reclassified into interest expense from accumulated other comprehensive income	$ 2,315	$ 20,578	$ 14,520
Unrealized gains on interest rate swaps included in accumulated other comprehensive income	82,418	23,558	(73,544)
Interest rate swap \| Level 2 \| Designated as hedging instrument
Interest Rate Swaps Measured at Fair Value
Fair value at beginning of period	(33,757)	(77,918)
Cash flow hedge ineffectiveness included in accumulated other comprehensive income	7	25
Losses on interest rate swaps reclassified into interest expense from accumulated other comprehensive income	2,315	20,578
Unrealized gains on interest rate swaps included in accumulated other comprehensive income	82,418	23,558
Fair value at end of period	$ 50,983	$ (33,757)	$ (77,918)