SEGMENT REPORTING - Net Real Estate and Secured Note Payable Balances for Each Segment (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Segment Reporting Information [Line Items]
Net real estate	$ 2,619,368	$ 2,587,486
Secured Notes Payable	75,000	75,000
Capital Expenditures	80,420	77,407
Debt issuance costs	250	648
Office
Segment Reporting Information [Line Items]
Net real estate	1,587,316	1,597,458
Secured Notes Payable	75,000	75,000
Capital Expenditures	61,510	56,720
Retail
Segment Reporting Information [Line Items]
Net real estate	469,733	478,037
Secured Notes Payable	0	0
Capital Expenditures	11,510	13,568
Multifamily
Segment Reporting Information [Line Items]
Net real estate	406,163	351,016
Capital Expenditures	5,094	5,637
Mixed-Use
Segment Reporting Information [Line Items]
Net real estate	156,156	160,975
Capital Expenditures	2,306	1,482
American Assets Trust, L.P.
Segment Reporting Information [Line Items]
Net real estate	2,619,368	2,587,486
Secured notes payable \| American Assets Trust, L.P.
Segment Reporting Information [Line Items]
Debt issuance costs	$ 151	$ 241

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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