DEBT - Summary of Total Secured Notes Payable Outstanding (Details) - USD ($) $ in Thousands	Jun. 23, 2017	Jan. 18, 2017	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Debt issuance costs, net of accumulated amortization of $565 and $542, respectively			$ (1,133)	$ (1,295)
Debt issuance costs, accumulated amortization			1,458	1,296
American Assets Trust, L.P. | Treasury Lock
Debt Instrument [Line Items]
Loss on derivatives	$ 500
Gain on derivatives		$ 10,400
American Assets Trust, L.P. | Secured notes payable, net
Debt Instrument [Line Items]
Principal Balance as of			75,000	75,000
Debt issuance costs, net of accumulated amortization of $565 and $542, respectively			(309)	(331)
Total Secured Notes Payable Outstanding			74,691	74,669
Debt issuance costs, accumulated amortization			565	542
American Assets Trust, L.P. | 5.08% City Center Bellevue, October 2027 | Secured notes payable, net
Debt Instrument [Line Items]
Principal Balance as of			$ 75,000	$ 75,000
Stated Interest Rate			5.08%
American Assets Trust, L.P. | Senior Guaranteed Notes, Series F | Treasury Lock
Debt Instrument [Line Items]
Effective interest rate (percent)			3.85%
American Assets Trust, L.P. | Senior Guaranteed Notes, Series D | Treasury Lock
Debt Instrument [Line Items]
Effective interest rate (percent)			3.87%