REAL ESTATE - Operating Results for Acquisition (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Real Estate [Line Items]
Revenues	$ 106,000	$ 111,023	$ 104,155	$ 101,470	$ 101,747	$ 98,286	$ 91,809	$ 83,986	$ 422,648	$ 375,828	$ 344,573
Operating expenses									307,914	275,959	255,992
OPERATING INCOME	27,073	31,003	28,316	28,342	25,715	27,669	26,423	20,062	114,734	99,869	88,581
Net income attributable to American Assets Trust, Inc.	$ 12,406	$ 16,369	$ 13,588	$ 13,514	$ 10,478	$ 12,895	$ 11,487	$ 1,733	55,877	$ 36,593	$ 35,588
Bel-Spring 520
Real Estate [Line Items]
Revenues									2,512
Operating expenses									2,417
OPERATING INCOME									95
Net income attributable to American Assets Trust, Inc.									$ 95