| Segment Information (Tables)
 | 9 Months Ended | 
| Sep. 30, 2021 | 
|---|
| Segment Information |  | 
| Schedule of performance measures |  
|  |  |  |  |  |  |  |  |  |  |  |  |  
|  |  | Three months ended   |  | Nine months ended  |  |  
|  |  | September 30,  |  | September 30,  |  |  
|  |  | 2021 |      | 2020 |  | 2021 |      | 2020 |  |  |  |  
|  |  | amounts in thousands |  |  
| GCI Holdings |  |  |    |   |    |  |  |    |   |    |  |  
| Consumer Revenue |  |  |    |   |    |  |  |    |   |    |  |  
| Wireless |  | $ |  33,485 |  |  — |  |  |  97,799 |  |  — |  |  
| Data |  |   |  53,608 |  |  — |  |  |  158,494 |  |  — |  |  
| Video |  |   |  18,273 |  |  — |  |  |  55,906 |  |  — |  |  
| Voice |  |   |  3,873 |  |  — |  |  |  11,108 |  |  — |  |  
| Business Revenue |  |   |  |  |  |  |  |  |  |  |  |  
| Wireless |  |   |  18,695 |  |  — |  |  |  56,006 |  |  — |  |  
| Data |  |   |  91,792 |  |  — |  |  |  267,826 |  |  — |  |  
| Video |  |   |  904 |  |  — |  |  |  2,586 |  |  — |  |  
| Voice |  |   |  5,748 |  |  — |  |  |  17,904 |  |  — |  |  
| Lease, grant, and revenue from subsidies |  |   |  19,310 |  |  — |  |  |  58,131 |  |  — |  |  
| Total GCI Holdings |  |  |  245,688 |  |  — |  |  |  725,760 |  |  — |  |  
| Corporate and other |  |  |  4,532 |  |  4,219 |  |  |  13,278 |  |  12,437 |  |  
| Total |  | $ |  250,220 |   |  4,219 |  |  |  739,038 |   |  12,437 |  |  | 
| Schedule of segment reporting information |  
|  |  |  |  |  |  |  |  |  |  |  |  
|  |  | Three months ended  September 30,  |  | Nine months ended September 30,  |  
|  |  | 2021 |  | 2020 |  | 2021 |  | 2020 |  |  |  
|  |  | amounts in thousands |  
| GCI Holdings |      | $ |  88,800 |      |  — |      |  |  273,515 |  |  — |  
| Charter |  |   |  5,295,000 |  |  4,625,000 |  |   |  14,967,000 |  |  13,501,000 |  
| Corporate and other |  |   |  (8,372) |  |  (14,270) |  |   |  (34,987) |  |  (26,658) |  
|  |  |   |  5,375,428 |  |  4,610,730 |  |   |  15,205,528 |  |  13,474,342 |  
| Eliminate equity method affiliate |  |   |  (5,295,000) |  |  (4,625,000) |  |   |  (14,967,000) |  |  (13,501,000) |  
| Consolidated Liberty Broadband |  | $ |  80,428 |  |  (14,270) |  |  |  238,528 |  |  (26,658) |   
|  |  |  |  |  |  |  |  |  |  
|  |  | September 30, 2021 |   |  
|  |  | Total |  | Investments |  | Capital |   |  
|  |  | assets |  | in affiliates |  | expenditures |   |  |  |  
|  |  | amounts in thousands |   |  
| GCI Holdings |      | $ |  3,517,437 |      |  397 |      |  91,198 |  |  
| Charter |  |   |  142,495,000 |   | — |   |  5,563,000 |  |  
| Corporate and other |  |   |  14,922,275 |   |  14,387,017 |   |  21 |  |  
|  |  |   |  160,934,712 |   |  14,387,414 |   |  5,654,219 |  |  
| Eliminate equity method affiliate |  |   |  (142,495,000) |   |  — |   |  (5,563,000) |  |  
| Consolidated Liberty Broadband |  | $ |  18,439,712 |   |  14,387,414 |   |  91,219 |  |  | 
| Schedule of reconciliation of segment Adjusted OIBDA to earnings (loss) before income taxes |  
|  |  |  |  |  |  |  |  |  |  |  |  
|  |  | Three months ended   |  | Nine months ended  |   |  
|  |  | September 30,  |  | September 30,  |   |  
|  |  | 2021 |  | 2020 |  | 2021 |      | 2020 |   |  |  |  
|  |  |  | amounts in thousands |   |  
| Adjusted OIBDA |      | $ |  80,428 |      |  (14,270) |      |  238,528 |      |  (26,658) |  |  
| Stock-based compensation |  |   |  (10,581) |  |  (2,002) |  |  (31,016) |   |  (5,736) |  |  
| Depreciation and amortization |  |   |  (68,130) |  |  (56) |  |  (198,766) |   |  (1,041) |  |  
| Litigation settlement, net of recoveries |  |  |  23,520 |  |  — |  |  (86,480) |  |  — |  |  
| Operating income (loss) |  |  |  25,237 |  |  (16,328) |  |  (77,734) |  |  (33,435) |  |  
| Interest expense |  |  |  (28,155) |  |  (3,719) |  |  (90,032) |   |  (14,711) |  |  
| Share of earnings (loss) of affiliates, net |  |   |  314,563 |  |  188,586 |  |  752,390 |   |  408,396 |  |  
| Gain (loss) on dilution of investment in affiliate |  |   |  (1,693) |  |  (35,284) |  |  (98,446) |   |  (140,610) |  |  
| Realized and unrealized gains (losses) on financial instruments, net |  |   |  (26,839) |  |  (39,324) |  |  (52,555) |   |  (39,324) |  |  
| Other, net |  |   |  14,788 |  |  8 |  |  29,382 |   |  199 |  |  
| Earnings (loss) before income taxes |  | $ |  297,901 |  |  93,939 |  |  463,005 |   |  180,515 |  |  |