EQUITY OF AMERICAN ASSETS TRUST, INC. - Computation of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
NUMERATOR
Net income	$ 15,397	$ 13,588	$ 36,063	$ 27,102
Less: Net income attributable to restricted shares	(190)	(154)	(379)	(309)
Less: Income from operations attributable to unitholders in the Operating Partnership	(3,224)	(2,852)	(7,565)	(5,688)
Net income attributable to American Assets Trust, Inc. stockholders	11,983	10,582	28,119	21,105
Income from operations attributable to American Assets Trust, Inc. common stockholders—basic	11,983	10,582	28,119	21,105
Plus: Income from operations attributable to unitholders in the Operating Partnership	3,224	2,852	7,565	5,688
Net income attributable to common stockholders—diluted	$ 15,207	$ 13,434	$ 35,684	$ 26,793
DENOMINATOR
Weighted average common shares outstanding—basic (in shares)	60,146,210	60,040,243	60,145,414	60,039,467
Effect of dilutive securities-conversion of Operating Partnership units (in shares)	16,181,537	16,181,537	16,181,537	16,181,537
Weighted average common shares outstanding - diluted (in shares)	76,327,747	76,221,780	76,326,951	76,221,004
Earnings per common share, basic (in USD per share)	$ 0.20	$ 0.18	$ 0.47	$ 0.35
Earnings per common share, diluted (in USD per share)	$ 0.20	$ 0.18	$ 0.47	$ 0.35