Capacity of plant

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- Definition

Contract Effective Date

+ References

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- Definition

Derivative Contract, Percentage

+ References

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- Definition

Number of Assigned Contracts

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- Definition

Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other Than Options Exercisable Percentage Year Four

+ References

No definition available.

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- Definition

Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other Than Options Exercisable Percentage Year Three

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- Definition

Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other Than Options Exercisable Percentage Year Two

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Exercise Price

+ References

No definition available.

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- Definition

Share Based Compensation Arrangement By Share Based Payment Award Expiry Period From Date Of Grant

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No definition available.

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- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

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- Definition

The day, month, and year (YYYY-MM-DD) that the dividend declared as of or prior to the financial reporting date will be paid in the subsequent period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

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- Definition

Equity impact of common stock cash dividends declared by an entity during the period. This element includes paid and unpaid dividends declared during the period.

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- Definition

The date as of when a holder must own the stock to be entitled to the dividend. The ex-dividend date is generally 3 days before the record date.

+ References

No definition available.

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- Definition

The date when the equity-based award expires as specified in the award agreement, which may be presented in a variety of ways (for example, year, month and year, day, month and year, quarter of a year).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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SUBSEQUENT EVENTS - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	1 Months Ended
	Mar. 31, 2011	Apr. 02, 2012 Stock-based Awards Grant Stock Appreciation Rights (SARs)	May 08, 2012 Dividend Declared	Apr. 18, 2012 New Contract Contract	Apr. 18, 2012 New Contract Minimum	Apr. 18, 2012 New Contract Maximum MW	Apr. 18, 2012 New Contract Nymex Heating Oil Swap Contract	Apr. 18, 2012 New Contract Ice Brent Swap Contract
Subsequent Event [Line Items]
Share based compensation arrangement by share based payment award granted		605,500
Exercise price of each SAR on the date of grant		$ 20.13
Expiration date of award grant		Seven years from the date of grant
Period of expiration of SARs from date of grant		7 years
Options exercisable percentage after 24 months		25.00%
Options exercisable percentage after 36 months		25.00%
Options exercisable percentage after 48 months		50.00%
Number of swap contracts entered with a bank				2
Contracts effective date					May 01, 2012	Mar. 31, 2013
Energy rate for the Puna complex as a result of fluctuations in oil prices						25
Derivative contract percentage							85.00%	15.00%
Cash dividends approved and authorized	$ 2,290		$ 1,800
Dividend per share declared	$ 0.05		$ 0.04
Recorded date of issued and outstanding shares			May 21, 2012
Dividend payment date			May 30, 2012