| **Information About the Company's Operating Segments - (Adjusted OIBDA) (Details) - USD ($) $ in Thousands** | 3 Months Ended |
|--------------------------------------------------------------------------------------------------------------|----------------|
||
| **Segment Reporting Information [Line Items]**                                                               |           |   |
| Adjusted OIBDA                                                                                               | $ 76,066       | $ 38,165 |
| Operating Segments                                                                                           |           |   |
| **Segment Reporting Information [Line Items]**                                                               |           |   |
| Adjusted OIBDA                                                                                               | 71,085         | 35,048 |
| Operating Segments | GCI Holdings                                                                            |           |   |
| **Segment Reporting Information [Line Items]**                                                               |           |   |
| Adjusted OIBDA                                                                                               | 86,395         | 44,471 |
| Operating Segments | Liberty Broadband                                                                       |           |   |
| **Segment Reporting Information [Line Items]**                                                               |           |   |
| Adjusted OIBDA                                                                                               | (4,981)        | (3,117) |
| Operating Segments | Corporate and other                                                                     |           |   |
| **Segment Reporting Information [Line Items]**                                                               |           |   |
| Adjusted OIBDA                                                                                               | (10,329)       | (6,306) |
| Consolidation, Eliminations                                                                                  |           |   |
| **Segment Reporting Information [Line Items]**                                                               |           |   |
| Adjusted OIBDA                                                                                               | $ 4,981        | $ 3,117 |

| X                                                                                                                                                                                                                                                                                                                           |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Adjusted Operating Income (Loss) Before Depreciation And Amortization
+ References
No definition available.
+ Details**Name:**gliba_AdjustedOperatingIncomeLossBeforeDepreciationAndAmortization**Namespace Prefix:**gliba_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                            |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - 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**Name:**us-gaap_SegmentReportingInformationLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**srt_ConsolidationItemsAxis=us-gaap_OperatingSegmentsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                     |
|-------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementBusinessSegmentsAxis=gliba_GCIHoldingsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                          |
|------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementBusinessSegmentsAxis=gliba_LibertyBroadbandMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                             |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementBusinessSegmentsAxis=us-gaap_CorporateAndOtherMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                      |
|--------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**srt_ConsolidationItemsAxis=srt_ConsolidationEliminationsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |