DERIVATIVE AND HEDGING ACTIVITIES (Details)																				12 Months Ended
	Jan. 05, 2023 USD ($)	Nov. 30, 2022 USD ($) property	Jan. 14, 2022 USD ($) property	Oct. 01, 2020 USD ($)	Aug. 11, 2020 USD ($)	Jul. 17, 2019 USD ($)	Jun. 20, 2019 USD ($)	Jun. 23, 2017 USD ($)	May 31, 2017 USD ($)	May 11, 2017 USD ($)	Apr. 25, 2017 USD ($)	Mar. 31, 2017	Jan. 18, 2017 USD ($)	May 02, 2016 USD ($)	Apr. 07, 2016 USD ($)	Mar. 29, 2016 USD ($)	Mar. 23, 2016 USD ($)	Mar. 01, 2016 USD ($)	Jan. 29, 2016 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Nov. 26, 2018	Mar. 01, 2018	May 23, 2017 USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Interest rate swap asset																				$ 9,986,000	$ 0
Interest rate swap liability																				(196,000)	$ (1,807,000)
Reclassified within twelve months																				1,100,000
Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount															$ 100,000,000	$ 150,000,000
Fixed interest rate on derivative															1.748%	1.88%
American Assets Trust, L.P. | Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Term of derivative contract									7 years		10 years	10 years			10 years	10 years
Gain on derivatives				$ 0
American Assets Trust, L.P. | Not Designated as Hedging Instrument | Treasury Lock
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Term of derivative contract					10 years
Notional Amount					$ 200,000,000
Fixed interest rate on derivative					0.7115%
American Assets Trust, L.P. | Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Term of derivative contract		2 years															7 years		7 years
Notional Amount																	$ 50,000,000		$ 100,000,000	$ 100,000,000
Fixed interest rate on derivative																	1.441%		1.4485%	4.13%
Gain/Loss recognized in other comprehensive income (loss)		$ 1,100,000											$ 10,400,000
Calculation period																	2 days		2 days
American Assets Trust, L.P. | Cash Flow Hedging | Designated as Hedging Instrument | Treasury Lock
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Term of derivative contract							10 years
Notional Amount							$ 100,000,000		$ 100,000,000		$ 100,000,000
Fixed interest rate on derivative							1.9925%		2.064%		2.313%
Gain/Loss recognized in other comprehensive income (loss)								$ (500,000)		$ 700,000
Gain on derivatives						$ 500,000
amortized to interest expense over period						10 years
Wells Fargo Bank, N.A. And Bank Of America, N.A. | American Assets Trust, L.P. | Not Designated as Hedging Instrument | Treasury Lock
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Term of derivative contract			5 years
Notional Amount			$ 50,000,000
Number of interest rate swap contracts | property			2
Calculation period			2 days
Wells Fargo Bank, N.A. And Bank Of America, N.A. | American Assets Trust, L.P. | Cash Flow Hedging | Designated as Hedging Instrument | Treasury Lock
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fixed interest rate on derivative			2.70%
Wells Fargo Bank, N.A. | American Assets Trust, L.P. | Not Designated as Hedging Instrument | Treasury Lock
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of interest rate swap contracts | property		1	1
Wells Fargo Bank, N.A. | American Assets Trust, L.P. | Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Swap, 3/31/2027 $150M
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount																$ 150,000,000
Wells Fargo Bank, N.A. | American Assets Trust, L.P. | Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Swap, 3/31/2027 $100M
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount															$ 100,000,000
Wells Fargo Bank, N.A. | American Assets Trust, L.P. | Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Swap, 1/5/2027
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount																				$ 50,000,000
Interest rate swap asset																				4,476,000
Wells Fargo Bank, N.A. | American Assets Trust, L.P. | Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Swap, 1/5/2025
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount																				150,000,000
Interest rate swap asset																				1,042,000
Bank Of America, N.A. | American Assets Trust, L.P. | Not Designated as Hedging Instrument | Treasury Lock
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of interest rate swap contracts | property			1
Bank Of America, N.A. | American Assets Trust, L.P. | Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Swap, 1/5/2027
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount																				50,000,000
Interest rate swap asset																				4,468,000
Mizuho Capital Markets LLC | American Assets Trust, L.P. | Not Designated as Hedging Instrument | Treasury Lock
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of interest rate swap contracts | property		1
Mizuho Capital Markets LLC | American Assets Trust, L.P. | Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Swap, 1/5/2025
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount																				75,000,000
Interest rate swap liability																				$ (196,000)
Wells Fargo Bank, National Association And Mizuho Capital Markets LLC | American Assets Trust, L.P. | Not Designated as Hedging Instrument | Treasury Lock
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Term of derivative contract		2 years
Notional Amount		$ 225,000,000
Number of interest rate swap contracts | property		2
Wells Fargo Bank, National Association And Mizuho Capital Markets LLC | American Assets Trust, L.P. | Cash Flow Hedging | Designated as Hedging Instrument | Treasury Lock
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fixed interest rate on derivative		4.17%
Calculation period		2 days
Term Loan B | American Assets Trust, L.P.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Face amount of debt																		$ 100,000,000	$ 100,000,000
Number of year amortization schedule		2 years																7 years	7 years
Term Loan B | American Assets Trust, L.P. | Subsequent Event
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of year amortization schedule	2 years
Term Loan B | American Assets Trust, L.P. | Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fixed interest rate on derivative																				3.15%			2.65%
Term Loan C | American Assets Trust, L.P.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Face amount of debt														$ 50,000,000			$ 50,000,000
Number of year amortization schedule														7 years			7 years
Term Loan C | American Assets Trust, L.P. | Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fixed interest rate on derivative																		3.14%		3.14%			2.64%
Unsecured Debt | American Assets Trust, L.P.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of year amortization schedule							11 years					10 years
Term Loan A | American Assets Trust, L.P.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Face amount of debt		$ 225,000,000
Term Loan A | American Assets Trust, L.P. | Subsequent Event
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Face amount of debt	$ 225,000,000
Term Loan A | American Assets Trust, L.P. | Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fixed interest rate on derivative																				2.70%		4.13%
Unsecured Debt | Term Loan B | American Assets Trust, L.P.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Face amount of debt																		$ 100,000,000
Unsecured Debt | Term Loan B | American Assets Trust, L.P. | Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fixed interest rate on derivative																		3.15%
Unsecured Debt | Term Loan C | American Assets Trust, L.P.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Face amount of debt														$ 50,000,000
Unsecured Debt | Senior Guaranteed Notes, Series E | American Assets Trust, L.P.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Face amount of debt																								$ 100,000,000
Number of year amortization schedule											12 years