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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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

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.

+ References

No definition available.

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- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

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- Definition

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

+ References

No definition available.

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- Definition

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.

+ References

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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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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13433-108611

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DERIVATIVE AND HEDGING (Details) - USD ($)								6 Months Ended
DERIVATIVE AND HEDGING (Details) - USD ($)	Mar. 31, 2017	May 02, 2016	Apr. 07, 2016	Mar. 29, 2016	Mar. 23, 2016	Mar. 01, 2016	Jan. 29, 2016	Jun. 30, 2016	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair Value Liability								$ 15,561,000	$ 1,686,000
American Assets Trust, L.P. \| Term Loan B
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Stated Maturity Date						Mar. 01, 2023
Face amount of debt						$ 100,000,000
Term of debt instrument						7 years
American Assets Trust, L.P. \| Term Loan B \| Unsecured term loans, net
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Stated Maturity Date								Mar. 01, 2023
Face amount of debt								$ 100,000,000
American Assets Trust, L.P. \| Term Loan C
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Stated Maturity Date		Mar. 01, 2023
Face amount of debt		$ 50,000,000
Term of debt instrument		7 years				7 years
American Assets Trust, L.P. \| Term Loan C \| Unsecured term loans, net
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Stated Maturity Date								Mar. 01, 2023
Face amount of debt								$ 50,000,000
American Assets Trust, L.P. \| Unsecured term loans, net \| Scenario, Forecast
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Term of debt instrument	10 years
American Assets Trust, L.P. \| Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative contract term			10 years	10 years
American Assets Trust, L.P. \| Interest Rate Swap \| Term Loan B
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative fixed interest rate (in percent)								3.15%
American Assets Trust, L.P. \| 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
Derivative fixed interest rate (in percent)			1.748%	1.88%
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]
Maturity Date								Jan. 09, 2019
Effective Date								Jan. 09, 2014
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]
Maturity Date								Mar. 01, 2023
Effective Date								Mar. 01, 2016
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]
Maturity Date								Mar. 01, 2023
Effective Date								May 02, 2016
Designated as Hedging Instrument \| Cash Flow Hedging \| Interest Rate Swap, 3/31/2027 \| Wells Fargo Bank, N.A.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Maturity Date								Mar. 31, 2027
Effective Date								Mar. 31, 2017
Designated as Hedging Instrument \| Cash Flow Hedging \| American Assets Trust, L.P. \| Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative contract term					7 years		7 years
Notional Amount					$ 50,000,000		$ 100,000,000
Maturity Date			Mar. 31, 2027	Mar. 31, 2027	Mar. 01, 2023		Mar. 01, 2023
Derivative fixed interest rate (in percent)					1.441%		1.4485%
Effective Date			Mar. 31, 2017	Mar. 31, 2017	May 02, 2016		Mar. 01, 2016
Designated as Hedging Instrument \| Cash Flow Hedging \| American Assets Trust, L.P. \| Interest Rate Swap, 1/9/2019 \| Bank of America, N.A.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount								$ 100,000,000
Fair Value Liability								2,995,000
Designated as Hedging Instrument \| Cash Flow Hedging \| American Assets Trust, L.P. \| Interest Rate Swap, 3/1/2023 \| U.S. Bank N.A.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount								100,000,000
Fair Value Liability								2,999,000
Designated as Hedging Instrument \| Cash Flow Hedging \| American Assets Trust, L.P. \| Interest Rate Swap, 3/1/2023 \| Wells Fargo Bank, N.A.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount								50,000,000
Fair Value Liability								1,487,000
Designated as Hedging Instrument \| Cash Flow Hedging \| American Assets Trust, L.P. \| Interest Rate Swap, 3/31/2027 $150M [Member] \| Wells Fargo Bank, N.A.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount								150,000,000
Fair Value Liability								5,601,000
Designated as Hedging Instrument \| Cash Flow Hedging \| American Assets Trust, L.P. \| Interest Rate Swap, 3/31/2027 \| Wells Fargo Bank, N.A.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount								100,000,000
Fair Value Liability								$ 2,479,000