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EQUITY OF AMERICAN ASSETS TRUST, INC. - Narrative (Details) $ in Millions		3 Months Ended		9 Months Ended
	Dec. 03, 2021 USD ($) sales_agent	Sep. 30, 2025 USD ($) shares	Sep. 30, 2024 USD ($) shares	Sep. 30, 2025 USD ($) shares	Sep. 30, 2024 USD ($) shares
Equity [Line Items]
Noncash compensation expense		$ 1.8	$ 2.0	$ 5.2	$ 5.3
Unrecognized compensation expense		$ 5.4		$ 5.4
Operating Partnership Units | American Assets Trust, L.P.
Equity [Line Items]
Weighted average unvested shares outstanding (in shares) | shares		606,062	581,314	602,093	583,247
At The Market Equity Program
Equity [Line Items]
Number of sales agents | sales_agent	5
Aggregate offering price of common share	$ 250.0
Common shares issued (in shares) | shares				0
Remaining capacity available for issuance		$ 250.0		$ 250.0

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