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.

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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

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

+ References

No definition available.

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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.

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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)
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- 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
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-SubTopic 10
-Section 50
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-Subparagraph (h)(1)(ii)
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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, 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
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-SubTopic 10
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-Paragraph 2
-Subparagraph (i)
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- Definition

Amount of cash inflow from realized tax benefit related to deductible compensation cost reported on the entity's tax return for equity instruments in excess of the compensation cost for those instruments recognized for financial reporting purposes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 20
-Section 55
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=96864182&loc=d3e11374-113907

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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.

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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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- Definition

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

+ References

No definition available.

+ Details

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 2
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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, 2017 USD ($) stock_plan shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares
Stock compensation plans
Number of stock incentive plans \| stock_plan	5
Stock-based compensation recognized in the income statement, before taxes	$ 2,885	$ 2,538	$ 2,754
Tax benefits from exercise of stock-based awards	$ 0	581	877
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	$ 2,420	2,118	2,443
Capitalized equity-based compensation cost	195	155	369
Tax benefits from exercise of stock-based awards	0	501	872
Nonqualified stock options
Stock compensation plans
Tax benefits from exercise of stock-based awards	$ 1,000	$ 581	$ 877
Granted (in shares) \| shares	0	0	0
Nonqualified stock options \| GSWC
Stock compensation plans
Tax benefits from exercise of stock-based awards	$ 1,000	$ 501	$ 872
Restricted Stock Units \| Employees and directors
Stock compensation plans
Stock-based compensation recognized in the income statement, before taxes	2,885	2,538	2,754
Restricted Stock Units \| Employees and directors \| GSWC
Stock compensation plans
Stock-based compensation recognized in the income statement, before taxes	$ 2,420	$ 2,118	$ 2,443
Performance awards
Stock compensation plans
Vesting period	3 years
2000 and 2008 Employee Plans \| Nonqualified stock options
Stock compensation plans
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	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
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%
Weighted Average [Member]
Stock compensation plans
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	1 year 6 months 30 days
Weighted Average [Member] \| Restricted Stock Units
Stock compensation plans
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	1 year 4 months 10 days