| **Earnings (Loss) per Common Share (Basic) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands** | 3 Months Ended | 12 Months Ended |
|---------------------------------------------------------------------------------------------------------------------------|----------------|-----------------|
||
| **Numerator [Abstract]**                                                                                                  |           |            |   |   |   |   |   |   |   |   |   |
| Net Income (Loss) Available to Common Stockholders, Basic                                                                 | $ (16,124)     | $ 7,943         | $ 3,415 | $ 1,099 | $ (8,760) | $ 17,631 | $ (15,627) | $ (19,269) | $ (3,667) | $ (26,025) | $ 7,557 |
| Class A Common Stock                                                                                                      |           |            |   |   |   |   |   |   |   |   |   |
| **Numerator [Abstract]**                                                                                                  |           |            |   |   |   |   |   |   |   |   |   |
| Net Income (Loss) Available to Common Stockholders, Basic                                                                 |           |            |   |   |   |   |   |   |   | (23,858) | 6,980 |
| Undistributed Earnings (Loss) Allocated to Participating Securities, Basic                                                |           |            |   |   |   |   |   |   |   | 0 | 385 |
| Undistributed Income (Loss) Available to Common Stockholders                                                              |           |            |   |   |   |   |   |   | $ (3,343) | $ (23,858) | $ 6,595 |
| **Denominator [Abstract]**                                                                                                |           |            |   |   |   |   |   |   |   |   |   |
| Weighted average common shares outstanding                                                                                |           |            |   |   |   |   |   |   | 32,526 | 34,764 | 36,112 |
| Basic net income (loss) attributable to General Communication, Inc. common stockholders per common share (USD per share)  | $ (0.47)       | $ 0.21          | $ 0.09 | $ 0.03 | $ (0.24) | $ 0.45 | $ (0.41) | $ (0.49) | $ (0.10) | $ (0.69) | $ 0.18 |
| Class B Common Stock                                                                                                      |           |            |   |   |   |   |   |   |   |   |   |
| **Numerator [Abstract]**                                                                                                  |           |            |   |   |   |   |   |   |   |   |   |
| Net Income (Loss) Available to Common Stockholders, Basic                                                                 |           |            |   |   |   |   |   |   |   | $ (2,167) | $ 577 |
| Undistributed Earnings (Loss) Allocated to Participating Securities, Basic                                                |           |            |   |   |   |   |   |   |   | 0 | 0 |
| Undistributed Income (Loss) Available to Common Stockholders                                                              |           |            |   |   |   |   |   |   | $ (324) | $ (2,167) | $ 577 |
| **Denominator [Abstract]**                                                                                                |           |            |   |   |   |   |   |   |   |   |   |
| Weighted average common shares outstanding                                                                                |           |            |   |   |   |   |   |   | 3,154 | 3,157 | 3,162 |
| Basic net income (loss) attributable to General Communication, Inc. common stockholders per common share (USD per share)  |           |            |   |   |   |   |   |   | $ (0.10) | $ (0.69) | $ 0.18 |

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Undistributed Income (Loss) Available to Common Stockholders
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.
+ References
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| - Definition
Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).
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| - Definition
Amount of undistributed earnings (loss) allocated to participating securities for the basic earnings (loss) per share or per unit calculation under the two-class method.
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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.
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