EQUITY OF AMERICAN ASSETS TRUST, INC. - Computation of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
NUMERATOR
Net income	$ 24,623	$ 20,666
Less: Net income attributable to restricted shares	(196)	(189)
Less: Income from operations attributable to unitholders in the Operating Partnership	(5,167)	(4,341)
NET INCOME ATTRIBUTABLE TO AMERICAN ASSETS TRUST, INC. STOCKHOLDERS	19,260	16,136
Income from operations attributable to American Assets Trust, Inc. common stockholders—basic	19,260	16,136
Plus: Income from operations attributable to unitholders in the Operating Partnership	5,167	4,341
Net income attributable to common stockholders—diluted	$ 24,427	$ 20,477
DENOMINATOR
Weighted average common shares outstanding—basic (in shares)	60,309,921	60,144,609
Effect of dilutive securities-conversion of Operating Partnership units (in shares)	16,181,537	16,181,537
Weighted average common shares outstanding - diluted (in shares)	76,491,458	76,326,146
Earnings per common share, basic (in dollars per share)	$ 0.32	$ 0.27
Earnings per common share, diluted (in dollars per share)	$ 0.32	$ 0.27