Represents the discount percentage for qualified low-income electric customers.

No definition available.

Name:	awr_DiscountPercentageForQualifiedLowIncomeElectricCustomers
Namespace Prefix:	awr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the discount percentage for qualified low-income water customers.

+ References

No definition available.

+ Details

Name:	awr_DiscountPercentageForQualifiedLowIncomeWaterCustomers
Namespace Prefix:	awr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of increase in revenue requirement for difference between the allocated general office costs authorized by the CPUC November 2010 Decision and what was then in rates for allocated general office costs.

+ References

No definition available.

+ Details

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

- Definition

Represents the term associated with a fixed-term security.

+ References

No definition available.

+ Details

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

- Definition

Represents the number of water regions for which two-way balancing account was established.

+ References

No definition available.

+ Details

Name:	awr_NumberOfWaterRegionsWithBalancingAccount
Namespace Prefix:	awr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the period of surcharge approved by CPUC for amounts collected through December 2013 to be applied to 2011.

+ References

No definition available.

+ Details

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

- Details

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

- Definition

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

+ References

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

+ Details

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

- Definition

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

+ References

+ Details

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

Regulatory Matters (Details 5) (GSWC, USD $)	12 Months Ended	1 Months Ended	12 Months Ended
Regulatory Matters (Details 5) (GSWC, USD $)	Dec. 31, 2014 water_region	Nov. 30, 2014	Dec. 31, 2013
Regulatory matters:
Total	$ 125,704,000us-gaap_NetRegulatoryAssets		$ 122,681,000us-gaap_NetRegulatoryAssets
Pension Costs and Other Postretirement Benefit Costs [Member]
Regulatory matters:
Regulatory asset	40,700,000
Number of water regions for which two-way balancing account was established	3
Total	43,426,000		20,241,000
Pension Costs and Other Postretirement Benefit Costs [Member] \| Two-way pension balancing account
Regulatory matters:
Regulatory asset	2,700,000
Water Revenue Adjustment Mechanism Net of Modified Cost Balancing Account [Member]
Regulatory matters:
Commercial paper, term	90 days
Total	(9,400,000)		16,345,000
Base revenue requirement adjustment mechanism
Regulatory matters:
Period of surcharge approved	12 months
Increase in Revenue Requirement, Recoverable through Surcharges		2,300,000
Total	7,761,000		8,725,000
Low income rate assistance balancing accounts
Regulatory matters:
Commercial paper, term	90 days
Increase in Revenue Requirement, Recoverable through Surcharges	700,000		1,200,000
Discount percentage for qualified low-income water customers	15.00%
Discount percentage for qualified low-income electric customers	20.00%
Total	$ 9,109,000		$ 9,979,000