REAL ESTATE - Operating Results for Acquisition (Details) - USD ($) $ in Thousands	3 Months Ended						7 Months Ended	9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2022	Sep. 30, 2021
Real Estate [Line Items]
Revenues	$ 111,023			$ 98,286				$ 316,648	$ 274,081
OPERATING INCOME	31,003			27,669				87,661	74,154
Net income attributable to American Assets Trust, Inc.	$ 16,369	$ 13,588	$ 13,514	$ 12,895	$ 11,487	$ 1,733		$ 43,471	$ 26,115
Office Building | Bel-Spring 520
Real Estate [Line Items]
Revenues							$ 1,733
Operating expenses							1,689
OPERATING INCOME							44
Net income attributable to American Assets Trust, Inc.							$ 44