Line of Credit Facility, Incremental Expansion of Borrowing Capacity

No definition available.

Name:	awr_LineofCreditFacilityIncrementalExpansionofBorrowingCapacity
Namespace Prefix:	awr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Ratio of Indebtedness to EBITDA

+ References

No definition available.

+ Details

Name:	awr_RatioofIndebtednesstoEBITDA
Namespace Prefix:	awr_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- 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:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- 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.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Indebtedness divided by net capital.

+ References

No definition available.

+ Details

Name:	us-gaap_RatioOfIndebtednessToNetCapital1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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- Details

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- Details

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Namespace Prefix:
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- Details

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Namespace Prefix:
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- Details

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- Details

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- Details

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- Details

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- Details

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Subsequent Events (Details) - USD ($)	Jul. 08, 2020	Jul. 01, 2020	Jul. 15, 2020	Mar. 31, 2020
Golden State Water Company [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.50%
Bear Valley Electric Service \| Subsequent Event [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Covenant Terms		3 years
Private Placement Notes \| Golden State Water Company [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount	$ 160,000,000.0
Note Payables 2.9% Percent Due 2040 \| Golden State Water Company [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount	$ 75,000,000.0
Debt Instrument, Interest Rate, Stated Percentage	2.90%
Syndicated Credit Facility \| Bear Valley Electric Service \| Subsequent Event [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Current Borrowing Capacity		$ 35,000,000
Line of Credit Facility, Incremental Expansion of Borrowing Capacity		$ 15,000,000
Note Payable 2.17 Percent Due 2030 \| Golden State Water Company [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount	$ 85,000,000.0
Debt Instrument, Interest Rate, Stated Percentage	2.17%
Parent Company [Member] \| Syndicated Credit Facility
Subsequent Event [Line Items]
Line of Credit Facility, Incremental Expansion of Borrowing Capacity				$ 35,000,000.0
Minimum [Member] \| Parent Company [Member] \| Syndicated Credit Facility
Subsequent Event [Line Items]
Line of Credit Facility, Current Borrowing Capacity				200,000,000.0
Minimum [Member] \| Parent Company [Member] \| Syndicated Credit Facility \| Subsequent Event [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Current Borrowing Capacity			$ 200,000,000.0
Maximum [Member] \| Golden State Water Company [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Ratio of Indebtedness to Net Capital	0.6667
Ratio of Indebtedness to EBITDA	8.00
Maximum [Member] \| Parent Company [Member] \| Syndicated Credit Facility
Subsequent Event [Line Items]
Line of Credit Facility, Current Borrowing Capacity				$ 260,000,000.0