DEBT - Summary of Total Secured Notes Payable Outstanding (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Debt issuance costs, net of accumulated amortization of $519 and $452, respectively	$ (1,457)	$ 0
Debt issuance costs, accumulated amortization	1,134	0
American Assets Trust, L.P. | Secured notes payable, net
Debt Instrument [Line Items]
Principal Balance	75,000	75,000
Debt issuance costs, net of accumulated amortization of $519 and $452, respectively	(354)	(422)
Total Notes Payable	74,646	74,578
Debt issuance costs, accumulated amortization	519	452
American Assets Trust, L.P. | Secured notes payable, net | 5.08% City Center Bellevue, October 2027
Debt Instrument [Line Items]
Principal Balance	$ 75,000	$ 75,000
Stated Interest Rate	5.08%