Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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Face (par) amount of debt instrument at time of issuance.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Fixed interest rate related to the interest rate derivative.

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Date the entity entered into the derivative contract, in CCYY-MM-DD format.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The effective portion of gains on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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The effective portion of losses on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Date the derivative contract matures, in CCYY-MM-DD format.

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Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

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Fair value as of the balance sheet date of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities.

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DERIVATIVE AND HEDGING ACTIVITIES (Details) - American Assets Trust, L.P. - USD ($)									9 Months Ended
	Jun. 23, 2017	May 31, 2017	May 11, 2017	Apr. 25, 2017	Mar. 31, 2017	Jan. 18, 2017	Apr. 07, 2016	Mar. 29, 2016	Sep. 30, 2017	May 23, 2017	Mar. 01, 2017
Senior Guaranteed Notes, Series D
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Term of debt instrument					10 years
Senior Guaranteed Notes, Series D \| Unsecured term loans, net
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Stated Maturity Date									Mar. 01, 2027
Face amount of debt											$ 250,000,000
Term Loan B \| Unsecured term loans, net
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Stated Maturity Date									Mar. 01, 2023
Term Loan C \| Unsecured term loans, net
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Stated Maturity Date									Mar. 01, 2023
Senior Guaranteed Notes, Series E \| Unsecured term loans, net
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Stated Maturity Date									May 23, 2029
Face amount of debt										$ 100,000,000
Term of debt instrument				12 years
Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative contract term		7 years		10 years			10 years	10 years
Interest Rate Swap \| Term Loan B
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative fixed interest rate (in percent)									3.15%
Interest Rate Swap \| Term Loan C
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative fixed interest rate (in percent)									3.14%
Designated as Hedging Instrument \| Cash Flow Hedging \| Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount							$ 100,000,000	$ 150,000,000
Maturity Date							Mar. 31, 2027	Mar. 31, 2027
Derivative fixed interest rate (in percent)							1.748%	1.88%
Effective Date							Mar. 31, 2017	Mar. 31, 2017
Gain recognized in other comprehensive income (loss)						$ 10,400,000
Designated as Hedging Instrument \| Cash Flow Hedging \| Interest Rate Swap, 1/9/2019 \| Bank of America, N.A.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount									$ 100,000,000
Maturity Date									Jan. 09, 2019
Effective Date									Jan. 09, 2014
Interest rate swap liability									$ (358,000)
Designated as Hedging Instrument \| Cash Flow Hedging \| Interest Rate Swap, 3/1/2023 \| U.S. Bank N.A.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount									$ 100,000,000
Maturity Date									Mar. 01, 2023
Effective Date									Mar. 01, 2016
Interest rate swap asset									$ 2,396,000
Designated as Hedging Instrument \| Cash Flow Hedging \| Interest Rate Swap, 3/1/2023 \| Wells Fargo Bank, N.A.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount									$ 50,000,000
Maturity Date									Mar. 01, 2023
Effective Date									May 02, 2016
Interest rate swap asset									$ 1,228,000
Designated as Hedging Instrument \| Cash Flow Hedging \| Treasury Lock
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount		$ 100,000,000		$ 100,000,000
Maturity Date		Jul. 26, 2017		May 18, 2017
Derivative fixed interest rate (in percent)		2.064%		2.313%
Gain recognized in other comprehensive income (loss)			$ 700,000
Loss recognized in other comprehensive income (loss)	$ 500,000