Name:	awr_IncreaseInRevenueRequirementRecoverableThroughSurcharges
Namespace Prefix:	awr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Represents the term associated with a fixed-term security.

No definition available.

Name:	awr_InvestmentTerm
Namespace Prefix:	awr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents amount billed to customers as surcharges.

No definition available.

Name:	awr_RegulatoryAssetAmountBilledToCustomersAsSurcharges
Namespace Prefix:	awr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents the regulatory asset not accruing carrying costs as of the balance sheet date.

No definition available.

Name:	awr_RegulatoryAssetNotAccruingCarryingCosts
Namespace Prefix:	awr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Represents the recovery periods of the surcharge billed to the customers.

No definition available.

Name:	awr_RegulatoryAssetRecoveryPeriods
Namespace Prefix:	awr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

-- None. No documentation exists for this element. --

No definition available.

Name:	awr_RegulatoryAssetsAndLiabilitiesLineItems
Namespace Prefix:	awr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Represents the weighted cost of capital (return on rate base), with an updated embedded debt cost and the settlement ROE.

No definition available.

Name:	awr_WeightedCostOfCapitalPercent
Namespace Prefix:	awr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The increase (decrease) during the reporting period in the value of other assets that are created when regulatory agencies permits public utilities to defer costs to the balance sheet.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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

The net amount of all regulatory assets less all regulatory liabilities as of the end of the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 340
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382

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

The amount of regulated water operating revenues recognized during the period.

No definition available.

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

The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period.

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

Name:	us-gaap_RegulatoryAssetAxis=awr_PensionCostsAndOtherPostretirementBenefitCostsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=awr_GeneralRateCaseMemorandumAccountsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=awr_WaterRevenueAdjustmentMechanismMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=awr_CostOfCapitalProceedingForWaterRegionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	dei_LegalEntityAxis=awr_GoldenStateWaterCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=awr_CostsDeferredForFutureRecoveryOnAerojetCaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=us-gaap_GainLossOnDerivativeInstrumentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=awr_FlowThroughTaxesNetMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=awr_WaterRevenueAdjustmentMechanismNetOfModifiedCostBalancingAccountMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryAssetAxis=awr_ModifiedCostBalancingAccountMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryLiabilityAxis=awr_RevenueSubjecttoRefundforTCJAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryLiabilityAxis=us-gaap_RevenueSubjectToRefundMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: