Base rate revenue for proposed rate increase (decrease).

No definition available.

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Namespace Prefix:	chgch_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Refund payments per customer during the period.

+ References

No definition available.

+ Details

Name:	chgch_CustomerRefundableFeesRefundPaymentsPerCustomer
Namespace Prefix:	chgch_
Data Type:	us-types:perUnitItemType
Balance Type:	na
Period Type:	duration

- Definition

Interruptible Storage Service Agreement Costs.

+ References

No definition available.

+ Details

Name:	chgch_InterruptibleStorageServiceAgreementCosts
Namespace Prefix:	chgch_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	chgch_RegulatoryMattersLineItems
Namespace Prefix:	chgch_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of refund payments made to customers during the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 13.A.4(a))

-URI http://asc.fasb.org/extlink&oid=27012821&loc=d3e214044-122780

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 13

-Section A

-Paragraph a

-Subsection 4

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of public utility's approved rate increase (decrease) by regulatory agency.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesApprovedRateIncreaseDecreasePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of public utility's requested rate increase (decrease) with regulatory agency.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesRequestedRateIncreaseDecreaseAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage of public utility's requested rate increase (decrease) with regulatory agency.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesRequestedRateIncreaseDecreasePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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Regulatory Matters (Details) (USD $)	0 Months Ended								6 Months Ended
Regulatory Matters (Details) (USD $)	Nov. 19, 2013	Oct. 23, 2013	Dec. 21, 2012	Jan. 02, 2014 Retail Customers [Member]	Jan. 02, 2014 Matanuska Electric Association, Inc. [Member]	Jan. 02, 2014 Seward [Member]	Nov. 19, 2013 Matanuska Electric Association, Inc. And Seward [Member]	May 30, 2014 Forecast [Member]	Jun. 30, 2014 Forecast [Member]
Regulatory Matters [Line Items]
Proposed increase (decrease) in base rate revenue	$ 16,000,000	$ (200,000)	$ 30,000,000
Proposed percentage increase decrease in base rate revenue	12.50%	(0.10%)	26.00%
Base rate revenue for proposed rate increase (decrease)		143,000,000	115,000,000				127,400,000
Increase (decrease) in system demand and energy rate				6.00%	8.00%	5.00%
Interruptible storage service agreement costs									400,000
Approximate total refunds to customers								$ 165,000
Approximate refund per customer								1.10