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, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
NUMERATOR
Net income	$ 13,588	$ 11,487	$ 27,102	$ 13,220
Less: Net income attributable to restricted shares	(154)	(135)	(309)	(272)
Less: Income from operations attributable to unitholders in the Operating Partnership	(2,852)	(2,411)	(5,688)	(2,750)
Net income attributable to American Assets Trust, Inc. stockholders	10,582	8,941	21,105	10,198
Income from operations attributable to American Assets Trust, Inc. common stockholders—basic	10,582	8,941	21,105	10,198
Plus: Income from operations attributable to unitholders in the Operating Partnership	2,852	2,411	5,688	2,750
Net income attributable to common stockholders—diluted	$ 13,434	$ 11,352	$ 26,793	$ 12,948
DENOMINATOR
Weighted average common shares outstanding-basic (in shares)	60,040,243	59,985,787	60,039,467	59,985,065
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)	76,221,780	76,167,324	76,221,004	76,166,602
Earnings per common share, basic (in USD per share)	$ 0.18	$ 0.15	$ 0.35	$ 0.17
Earnings per common share, diluted (in USD per share)	$ 0.18	$ 0.15	$ 0.35	$ 0.17