DERIVATIVE AND HEDGING ACTIVITIES (Details) - Designated as Hedging Instrument - Cash Flow Hedging - American Assets Trust, L.P.	9 Months Ended
	Sep. 30, 2018 USD ($)
Interest Rate Swap, 1/9/2019 | Bank of America, N.A.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	$ 100,000,000
Effective Date	Jan. 09, 2014
Maturity Date	Jan. 09, 2019
Interest rate swap asset	$ 152,000
Interest Rate Swap, 3/1/2023 | U.S. Bank N.A.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	$ 100,000,000
Effective Date	Mar. 01, 2016
Maturity Date	Mar. 01, 2023
Interest rate swap asset	$ 6,135,000
Interest Rate Swap, 3/1/2023 | Wells Fargo Bank, N.A.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	$ 50,000,000
Effective Date	May 02, 2016
Maturity Date	Mar. 01, 2023
Interest rate swap asset	$ 3,097,000