REAL ESTATE - Operating Results for Acquisition (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Real Estate [Line Items]
Revenues	$ 104,155		$ 91,809		$ 205,625	$ 175,795
OPERATING INCOME	28,316		26,423		56,658	46,485
Net income attributable to American Assets Trust, Inc.	$ 13,588	$ 13,514	$ 11,487	$ 1,733	27,102	$ 13,220
Office Building | Bel-Spring 520
Real Estate [Line Items]
Revenues					953
Operating expenses					947
OPERATING INCOME					6
Net income attributable to American Assets Trust, Inc.					$ 6