Represents the number of stock incentive plans of the entity.

No definition available.

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- Definition

Period in which 33% vesting rights is earned by awardeed of the grant, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

Represents the common stock entitled to be received under each share-based payment award.

+ References

No definition available.

+ Details

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- Definition

The period of time, from the grant date until the time at which the share-based [option] award expires.

+ References

No definition available.

+ Details

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- Definition

Share Based Compensation Arrangements by Share Based Payment Award Options, Minimum Age for Awards to Vest Immediately

+ References

No definition available.

+ Details

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- Definition

Description of award terms as to how many shares or portion of an award are no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in the third year from the date of grant, thereby giving the employee the legal right to convert the award to shares, expressed as a percentage.

+ References

No definition available.

+ Details

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 14.F)
-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 14
-Section F

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the compensation cost capitalized during the period arising from equity-based compensation arrangements (for example, shares of stock, units, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Data Type:	xbrli:durationItemType
Balance Type:	na
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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

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Gross number of share options (or share units) granted during the period.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
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- Details

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- Details

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- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_PerformanceSharesMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	us-gaap_PlanNameAxis=awr_EmployeePlans2000And2008Member
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Data Type:	na
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- Details

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Stock-Based Compensation Plans (Details) $ in Thousands	12 Months Ended
Stock-Based Compensation Plans (Details) $ in Thousands	Dec. 31, 2015 USD ($) stock_plan shares	Dec. 31, 2014 USD ($) shares	Dec. 31, 2013 USD ($) shares
Stock compensation plans
Number of stock incentive plans \| stock_plan	4
Stock-based compensation recognized in the income statement, before taxes	$ 2,754	$ 2,222	$ 2,009
Immediate vesting for employees of certain age and above	55 years
GSWC
Stock compensation plans
Stock-based compensation recognized in the income statement, before taxes	$ 2,443	1,748	1,647
Capitalized equity-based compensation cost	$ 369	$ 255	$ 334
Nonqualified stock options
Stock compensation plans
Granted (in shares) \| shares	0	0	0
Nonqualified stock options \| Employees and directors
Stock compensation plans
Stock-based compensation recognized in the income statement, before taxes	$ 0	$ 0	$ 9
Nonqualified stock options \| Employees and directors \| GSWC
Stock compensation plans
Stock-based compensation recognized in the income statement, before taxes	0	0	8
Restricted Stock Units \| Employees and directors
Stock compensation plans
Stock-based compensation recognized in the income statement, before taxes	2,754	2,222	2,000
Restricted Stock Units \| Employees and directors \| GSWC
Stock compensation plans
Stock-based compensation recognized in the income statement, before taxes	$ 2,443	$ 1,748	$ 1,639
Performance awards
Stock compensation plans
Vesting period	3 years
2000 and 2008 Employee Plans \| Nonqualified stock options
Stock compensation plans
Expiration term	10 years
Vesting period	3 years
Percentage of rights vesting in the first two years from the date of grant	33.00%
Percentage of rights vesting in the third year from the date of grant	34.00%
2000 and 2008 Employee Plans \| Restricted Stock Units
Stock compensation plans
Vesting period	3 years
Common stock entitled to be received under each award \| shares	1
Percentage of rights vesting in the first two years from the date of grant	33.00%
Percentage of rights vesting in the third year from the date of grant	34.00%
2000 and 2008 Employee Plans \| Performance awards
Stock compensation plans
Vesting period	3 years
Percentage of rights vesting in the first two years from the date of grant	33.00%
Percentage of rights vesting in the third year from the date of grant	34.00%
2003 Directors Plan \| Nonqualified stock options
Stock compensation plans
Expiration term	10 years
Vesting period	3 years