| **Business and Summary of Significant Accounting Principles (Diluted EPS calculations) (Details) (USD $)In Thousands, except Per Share data, unless otherwise specified** | 3 Months Ended                                                                                                                                              |
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| Common Stock - Class A [Member]                                                                                                                                           |                                                                                                                                                        |   |
| **Class of Stock [Line Items]**                                                                                                                                           |                                                                                                                                                        |   |
| Allocation of undistributed earnings (loss) for basic computation                                                                                                         | $ (17,723)gncma_UndistributedIncomeLossAvailabletoCommonStockholders/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember                         | $ 999gncma_UndistributedIncomeLossAvailabletoCommonStockholders/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember |
| Reallocation of undistributed earnings (loss) as a result of conversion of Class B to Class A shares                                                                      | (1,546)gncma_DilutiveSecuritiesEffectOnBasicEarningsPerShareConversionofCommonStock/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember          | 88gncma_DilutiveSecuritiesEffectOnBasicEarningsPerShareConversionofCommonStock/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember |
| Net income (loss) adjusted for allocation of undistributed earnings and effect of contracts that may be settled in cash or shares                                         | (19,269)us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember                            | 1,087us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember |
| Number of shares used in basic computation                                                                                                                                | 36,217us-gaap_WeightedAverageNumberOfSharesOutstandingBasic/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember                                  | 36,081us-gaap_WeightedAverageNumberOfSharesOutstandingBasic/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember |
| Conversion of Class B to Class A common shares outstanding                                                                                                                | 3,159gncma_IncrementalCommonSharesAttributableToConversionFromOneClassOfCommonStockToAnother/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember | 3,163gncma_IncrementalCommonSharesAttributableToConversionFromOneClassOfCommonStockToAnother/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember |
| Unexercised stock options                                                                                                                                                 | 0us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember                  | 118us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember |
| Number of shares used in per share computation                                                                                                                            | 39,376us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember                                | 39,362us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember |
| Diluted net income (loss) attributable to GCI common stockholders per common share                                                                                        | $ (0.49)us-gaap_EarningsPerShareDiluted/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember                                                      | $ 0.03us-gaap_EarningsPerShareDiluted/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassAMember |
| Common Stock - Class B [Member]                                                                                                                                           |                                                                                                                                                        |   |
| **Class of Stock [Line Items]**                                                                                                                                           |                                                                                                                                                        |   |
| Allocation of undistributed earnings (loss) for basic computation                                                                                                         | (1,546)gncma_UndistributedIncomeLossAvailabletoCommonStockholders/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember                            | 88gncma_UndistributedIncomeLossAvailabletoCommonStockholders/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember |
| Reallocation of undistributed earnings (loss) as a result of conversion of Class B to Class A shares                                                                      | 0gncma_DilutiveSecuritiesEffectOnBasicEarningsPerShareConversionofCommonStock/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember                | 0gncma_DilutiveSecuritiesEffectOnBasicEarningsPerShareConversionofCommonStock/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember |
| Net income (loss) adjusted for allocation of undistributed earnings and effect of contracts that may be settled in cash or shares                                         | $ (1,546)us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember                           | $ 88us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember |
| Number of shares used in basic computation                                                                                                                                | 3,159us-gaap_WeightedAverageNumberOfSharesOutstandingBasic/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember                                   | 3,163us-gaap_WeightedAverageNumberOfSharesOutstandingBasic/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember |
| Conversion of Class B to Class A common shares outstanding                                                                                                                | 0gncma_IncrementalCommonSharesAttributableToConversionFromOneClassOfCommonStockToAnother/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember     | 0gncma_IncrementalCommonSharesAttributableToConversionFromOneClassOfCommonStockToAnother/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember |
| Unexercised stock options                                                                                                                                                 | 0us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember                  | 0us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember |
| Number of shares used in per share computation                                                                                                                            | 3,159us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember                                 | 3,163us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember |
| Diluted net income (loss) attributable to GCI common stockholders per common share                                                                                        | $ (0.49)us-gaap_EarningsPerShareDiluted/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember                                                      | $ 0.03us-gaap_EarningsPerShareDiluted/ us-gaap_StatementClassOfStockAxis= us-gaap_CommonClassBMember |

| X                                                                                                                                                                                                                                                                                                                                                  |
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| - Definition
Dilutive Securities Effect On Basic Earnings Per Share, Conversion of Common Stock
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                        |
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| - Definition
Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible class B stock using if-converted method.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                          |
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| - Definition
Undistributed Income (Loss) Available to Common Stockholders
+ References
No definition available.
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| - Definition
The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1252-109256Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.21) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
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| - Definition
Net Income or Loss Available to Common Stockholders plus adjustments resulting from the assumption that dilutive convertible securities were converted, options or warrants were exercised, or that other shares were issued upon the satisfaction of certain conditions.
+ References
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.
+ References
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| - Definition
Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.
+ References
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