EQUITY OF AMERICAN ASSETS TRUST, INC. - Narrative (Details) $ in Millions		3 Months Ended		6 Months Ended
	Dec. 03, 2021 USD ($) sales_agent	Jun. 30, 2024 USD ($) shares	Jun. 30, 2023 USD ($) shares	Jun. 30, 2024 USD ($) shares	Jun. 30, 2023 USD ($) shares
Equity [Line Items]
Noncash compensation expense		$ 1.7	$ 2.1	$ 3.4	$ 4.1
Unrecognized compensation expense		$ 6.1		$ 6.1
Operating Partnership Units | American Assets Trust, L.P.
Equity [Line Items]
Weighted average unvested shares outstanding (in shares) | shares		583,239	571,999	584,225	572,623
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