v3.25.4

DEBT - Narrative (Details)												12 Months Ended
	Nov. 13, 2025 extension	Feb. 03, 2025 USD ($)	Dec. 02, 2024 USD ($)	Sep. 17, 2024 USD ($)	Sep. 10, 2024 USD ($)	Jul. 19, 2024 USD ($)	Jul. 18, 2024 USD ($)	Jan. 05, 2023 USD ($) extension	Jan. 05, 2022 USD ($) extension	Jan. 26, 2021 USD ($)	Oct. 31, 2014 USD ($)	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Sep. 09, 2024 USD ($)	Jul. 30, 2019 USD ($)	Jul. 19, 2017 USD ($)	May 23, 2017 USD ($)	Mar. 01, 2017 USD ($)
Debt Instrument [Line Items]
Repayments of unsecured debt												$ 225,000,000	$ 0	$ 150,000,000
Repayment of unsecured line of credit												0	100,000,000	36,000,000
Borrowings												0	100,000,000	0
American Assets Trust, L.P.
Debt Instrument [Line Items]
Repayments of unsecured debt												225,000,000	0	150,000,000
Repayment of unsecured line of credit												0	100,000,000	36,000,000
Borrowings												$ 0	$ 100,000,000	$ 0
American Assets Trust, L.P. | Treasury Locks
Debt Instrument [Line Items]
Notional amount					$ 150,000,000										$ 150,000,000
Loss on derivatives					$ 1,300,000
3.375% Senior Unsecured Notes | American Assets Trust, L.P.
Debt Instrument [Line Items]
Stated Interest Rate										3.375%
3.375% Senior Unsecured Notes | American Assets Trust, L.P. | Unsecured term loan
Debt Instrument [Line Items]
Stated Interest Rate										3.375%		3.375%
Face amount of debt										$ 500,000,000
Note offering percent										0.98935
Effective interest rate (percent)										3.502%
Proceeds from debt, net of issuance costs										$ 489,700,000
Maximum aggregate debt ratio												60.00%
Minimum debt service ratio												1.5
Maximum secured debt ratio												40.00%
Minimum maintenance of total unencumbered assets												150.00%
6.150% Senior Notes | American Assets Trust, L.P.
Debt Instrument [Line Items]
Stated Interest Rate				6.15%
6.150% Senior Notes | American Assets Trust, L.P. | Treasury Locks
Debt Instrument [Line Items]
Effective interest rate (percent)												6.209%
6.150% Senior Notes | American Assets Trust, L.P. | Unsecured term loan
Debt Instrument [Line Items]
Stated Interest Rate				6.15%								6.15%
Face amount of debt				$ 525,000,000
Note offering percent				0.99671
Effective interest rate (percent)				6.194%								6.209%
Proceeds from debt, net of issuance costs				$ 518,200,000
Senior Guaranteed Notes, Series A | American Assets Trust, L.P. | Unsecured term loan
Debt Instrument [Line Items]
Repayments of unsecured debt										150,000,000
Make-whole payment										3,900,000
Second Amended and Restated Credit Facility | American Assets Trust, L.P. | Unsecured term loan
Debt Instrument [Line Items]
Repayment of unsecured line of credit										$ 100,000,000
Revolver Loan | American Assets Trust, L.P. | Unsecured term loan
Debt Instrument [Line Items]
Repayments of unsecured debt				$ 100,000,000
Senior Guaranteed Notes, Series B | American Assets Trust, L.P. | Unsecured term loan
Debt Instrument [Line Items]
Repayments of unsecured debt			$ 100,000,000
Senior Guaranteed Notes, Series C | American Assets Trust, L.P. | Unsecured term loan
Debt Instrument [Line Items]
Stated Interest Rate												4.50%
Repayments of unsecured debt		$ 100,000,000
Note Purchase Agreement | American Assets Trust, L.P. | Senior Guaranteed Notes
Debt Instrument [Line Items]
Face amount of debt											$ 350,000,000
Partial debt repayment, minimum percentage of principal											5.00%
Full debt repayment percentage of principal plus a make-whole amount											100.00%
Note Purchase Agreement | American Assets Trust, L.P. | Senior Guaranteed Notes, Series A
Debt Instrument [Line Items]
Stated Interest Rate											4.04%
Face amount of debt											$ 150,000,000
Note Purchase Agreement | American Assets Trust, L.P. | Senior Guaranteed Notes, Series B
Debt Instrument [Line Items]
Stated Interest Rate											4.45%
Face amount of debt											$ 100,000,000
Note Purchase Agreement | American Assets Trust, L.P. | Senior Guaranteed Notes, Series C
Debt Instrument [Line Items]
Stated Interest Rate											4.50%
Face amount of debt											$ 100,000,000
Senior Guaranteed Notes, Series D | American Assets Trust, L.P. | Treasury Locks
Debt Instrument [Line Items]
Effective interest rate (percent)												3.87%
Senior Guaranteed Notes, Series D | American Assets Trust, L.P. | Unsecured term loan
Debt Instrument [Line Items]
Stated Interest Rate												4.29%							4.29%
Face amount of debt																			$ 250,000,000
Senior Guaranteed Notes, Series E | American Assets Trust, L.P. | Treasury Locks
Debt Instrument [Line Items]
Effective interest rate (percent)												4.18%
Senior Guaranteed Notes, Series E | American Assets Trust, L.P. | Unsecured term loan
Debt Instrument [Line Items]
Stated Interest Rate												4.24%						4.24%
Face amount of debt																		$ 100,000,000
Senior Guaranteed Notes, Series F | American Assets Trust, L.P. | Unsecured term loan
Debt Instrument [Line Items]
Stated Interest Rate																	3.78%
Face amount of debt																	$ 100,000,000
Repayments of unsecured debt						$ 100,000,000
Borrowings							$ 100,000,000
Senior Guaranteed Notes, Series G | American Assets Trust, L.P. | Treasury Locks
Debt Instrument [Line Items]
Effective interest rate (percent)												3.88%
Senior Guaranteed Notes, Series G | American Assets Trust, L.P. | Unsecured term loan
Debt Instrument [Line Items]
Stated Interest Rate												3.91%				3.91%
Face amount of debt																$ 150,000,000
Third Amended and Restated Credit Facility | American Assets Trust, L.P.
Debt Instrument [Line Items]
Borrowings (up to)									$ 500,000,000
Third Amended and Restated Credit Facility | American Assets Trust, L.P. | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate									1.00%
Third Amended and Restated Credit Facility | American Assets Trust, L.P. | Unsecured term loan
Debt Instrument [Line Items]
Borrowings (up to)									$ 100,000,000
Number of extensions available | extension									2
Extension term									6 months
Third Amended and Restated Credit Facility | American Assets Trust, L.P. | Unsecured term loan | SOFR
Debt Instrument [Line Items]
Basis spread on variable rate									1.00%
Third Amended and Restated Credit Facility | American Assets Trust, L.P. | Unsecured term loan | Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate									0.50%
Third Amended and Restated Credit Facility | American Assets Trust, L.P. | Unsecured term loan | Minimum | SOFR
Debt Instrument [Line Items]
Basis spread on variable rate									1.20%
Third Amended and Restated Credit Facility | American Assets Trust, L.P. | Unsecured term loan | Minimum | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate									0.20%
Third Amended and Restated Credit Facility | American Assets Trust, L.P. | Unsecured term loan | Maximum | SOFR
Debt Instrument [Line Items]
Basis spread on variable rate									1.70%
Third Amended and Restated Credit Facility | American Assets Trust, L.P. | Unsecured term loan | Maximum | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate									0.70%
Third Amended and Restated Credit Facility | American Assets Trust, L.P. | Unsecured line of credit, net
Debt Instrument [Line Items]
Debt issuance costs, net, revolving credit facility												$ 250,000
Weighted average interest rate												5.45%
Maximum leverage ratio of revolving credit facility									60.00%
Maximum secured leverage ratio on revolving credit facility									40.00%
Minimum fixed charge coverage ratio covenant threshold									1.50
Minimum interest coverage ratio covenant threshold									175.00%
Maximum unsecured leverage ratio (in percentage)									60.00%
Maximum recourse indebtedness of total asset value									15.00%
Percentage annual distributions cannot exceed funds from operations									95.00%
Third Amended and Restated Credit Facility | American Assets Trust, L.P. | Unsecured line of credit, net | Revolving Credit Facility
Debt Instrument [Line Items]
Borrowings (up to)									$ 400,000,000
Number of extensions available | extension	1
Extension term	6 months
Third Amended and Restated Credit Facility | American Assets Trust, L.P. | Unsecured line of credit, net | Revolving Credit Facility | Minimum | SOFR
Debt Instrument [Line Items]
Basis spread on variable rate									1.05%
Third Amended and Restated Credit Facility | American Assets Trust, L.P. | Unsecured line of credit, net | Revolving Credit Facility | Minimum | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate									0.10%
Third Amended and Restated Credit Facility | American Assets Trust, L.P. | Unsecured line of credit, net | Revolving Credit Facility | Maximum | SOFR
Debt Instrument [Line Items]
Basis spread on variable rate									1.50%
Third Amended and Restated Credit Facility | American Assets Trust, L.P. | Unsecured line of credit, net | Revolving Credit Facility | Maximum | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate									0.50%
Term Loan A | American Assets Trust, L.P. | Interest Rate Swap
Debt Instrument [Line Items]
Fixed interest rate on derivative												2.70%
Term Loan B | American Assets Trust, L.P. | Unsecured term loan
Debt Instrument [Line Items]
Face amount of debt								$ 150,000,000
Term Loan C | American Assets Trust, L.P. | Unsecured term loan
Debt Instrument [Line Items]
Face amount of debt								$ 75,000,000
Term Loan B & Term Loan C | American Assets Trust, L.P. | Unsecured term loan
Debt Instrument [Line Items]
Number of extensions available | extension								1
Extension term								12 months

X

- Definition

Debt Instrument, Covenants, Maximum Aggregate Debt Ratio

+ References

No definition available.

+ Details

Name:	aat_DebtInstrumentCovenantsMaximumAggregateDebtRatio
Namespace Prefix:	aat_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Debt Instrument, Covenants, Maximum Secured Debt Ratio

+ References

No definition available.

+ Details

Name:	aat_DebtInstrumentCovenantsMaximumSecuredDebtRatio
Namespace Prefix:	aat_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Debt Instrument, Covenants, Minimum Debt Service Ratio

+ References

No definition available.

+ Details

Name:	aat_DebtInstrumentCovenantsMinimumDebtServiceRatio
Namespace Prefix:	aat_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Debt Instrument, Covenants, Minimum Maintenance Of Total Unencumbered Assets

+ References

No definition available.

+ Details

Name:	aat_DebtInstrumentCovenantsMinimumMaintenanceOfTotalUnencumberedAssets
Namespace Prefix:	aat_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Debt Instrument, Extension Options

+ References

No definition available.

+ Details

Name:	aat_DebtInstrumentExtensionOptions
Namespace Prefix:	aat_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Debt Instrument, Extension Term

+ References

No definition available.

+ Details

Name:	aat_DebtInstrumentExtensionTerm
Namespace Prefix:	aat_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Debt Instrument, Face Issuance Percent

+ References

No definition available.

+ Details

Name:	aat_DebtInstrumentFaceIssuancePercent
Namespace Prefix:	aat_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Debt Instrument, Partial Repayment, Minimum Percentage of Principal

+ References

No definition available.

+ Details

Name:	aat_DebtInstrumentPartialRepaymentMinimumPercentageofPrincipal
Namespace Prefix:	aat_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Debt Instrument, Prepayment, Percentage Of Principal Plus A Stated Amount

+ References

No definition available.

+ Details

Name:	aat_DebtInstrumentPrepaymentPercentageOfPrincipalPlusAStatedAmount
Namespace Prefix:	aat_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Maximum leverage percentage of revolving credit facility.

+ References

No definition available.

+ Details

Name:	aat_LineOfCreditFacilityMaximumLeveragePercentage
Namespace Prefix:	aat_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Make Whole Payment for Debt Extinguishment

+ References

No definition available.

+ Details

Name:	aat_MakeWholePaymentForDebtExtinguishment
Namespace Prefix:	aat_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Maximum Recourse Indebtedness Of Total Asset Value

+ References

No definition available.

+ Details

Name:	aat_MaximumRecourseIndebtednessOfTotalAssetValue
Namespace Prefix:	aat_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Maximum Secured Leverage Ratio On Revolving Credit Facility

+ References

No definition available.

+ Details

Name:	aat_MaximumSecuredLeverageRatioOnRevolvingCreditFacility
Namespace Prefix:	aat_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Maximum Unsecured Leverage Ratio

+ References

No definition available.

+ Details

Name:	aat_MaximumUnsecuredLeverageRatio
Namespace Prefix:	aat_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Minimum Fixed Charge Coverage Ratio On Revolving Credit Facility

+ References

No definition available.

+ Details

Name:	aat_MinimumFixedChargeCoverageRatioOnRevolvingCreditFacility
Namespace Prefix:	aat_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Minimum Unsecured Interest Coverage Ratio

+ References

No definition available.

+ Details

Name:	aat_MinimumUnsecuredInterestCoverageRatio
Namespace Prefix:	aat_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Percentage limit on annual distributions in relation to funds from operations.

+ References

No definition available.

+ Details

Name:	aat_PercentageLimitOnAnnualDistributionsInRelationToFundsFromOperations
Namespace Prefix:	aat_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482949/835-30-55-8

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69B

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69C
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69C

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482900/835-30-50-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-2

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482949/835-30-55-8

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(a)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482900/835-30-50-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-6

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(a)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-8A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 235
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477314/942-235-S99-2

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-4

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-3

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482949/835-30-55-8

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 9: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69B

Reference 10: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69C
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69C

Reference 11: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69E
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69E

Reference 12: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69F
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69F

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 15: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1D
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1D
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1D
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1E

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1E

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1E

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1F
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1F

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1F
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1F

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1F
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1F

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1F
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1F

Reference 29: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1I

Reference 30: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-2

Reference 31: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482900/835-30-50-1

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479359/835-30-S45-1

+ Details

Name:	us-gaap_DebtIssuanceCostsLineOfCreditArrangementsNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of decrease in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-4A

+ Details

Name:	us-gaap_DerivativeLossOnDerivative
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 181
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480401/815-10-55-181

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-1B

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-1A

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Fixed interest rate that will be received or paid upon exercise of the interest rate swaption contract.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeSwaptionInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The effective interest rate during the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_LineOfCreditFacilityInterestRateDuringPeriod
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 14
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-14

+ Details

Name:	us-gaap_ProceedsFromDebtNetOfIssuanceCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

The cash inflow from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with either short term or long term maturity that is uncollateralized (where debt is not backed by the pledge of collateral).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-14

+ Details

Name:	us-gaap_ProceedsFromUnsecuredLinesOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 15
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-15

+ Details

Name:	us-gaap_RepaymentsOfLinesOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

The cash outflow to repay long-term debt that is not secured by collateral. Excludes repayments of tax exempt unsecured debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 15
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-15

+ Details

Name:	us-gaap_RepaymentsOfUnsecuredDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

Name:	dei_LegalEntityAxis=aat_AmericanAssetsTrustL.P.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_TreasuryLockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_A3375SeniorUnsecuredNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_A6.150SeniorUnsecuredNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_SeniorGuaranteedNotesSeriesAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_SecondAmendedandRestatedCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_RevolverLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_SeniorGuaranteedNotesSeriesBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_SeniorGuaranteedNotesSeriesCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_NotePurchaseAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=aat_SeniorGuaranteedNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=aat_SeniorGuaranteedNotesSeriesAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=aat_SeniorGuaranteedNotesSeriesBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=aat_SeniorGuaranteedNotesSeriesCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_SeniorGuaranteedNotesSeriesDMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_SeniorGuaranteedNotesSeriesEMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_SeniorGuaranteedNotesSeriesFMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_SeniorGuaranteedNotesSeriesGMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_ThirdAmendedAndRestatedCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_SecuredOvernightFinancingRateSofrMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_VariableRateAxis=aat_FederalFundsRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_TermLoanAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_TermLoanBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_TermLoanCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=aat_TermLoanBTermLoanCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: