Information About GCI Liberty's Operating Segments (Tables)
   | 
3 Months Ended | 
Mar. 31, 2018  | 
| Segment Reporting [Abstract] | 
 
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| Reconciliation of Revenue from Segments to Consolidated | 
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   | 
Three months ended March 31,  | 
 
   | 
2018  | 
   | 
2017  | 
 
   | 
Revenue  | 
   | 
Adjusted OIBDA  | 
   | 
Revenue  | 
   | 
Adjusted OIBDA  | 
 
   | 
amounts in thousands  | 
 
GCI Holdings  | 
$  | 
56,792  | 
 
  | 
   | 
19,748  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
 
Liberty Broadband  | 
11,791  | 
 
  | 
   | 
4,560  | 
 
  | 
   | 
3,140  | 
 
  | 
   | 
(3,961  | 
)  | 
 
Corporate and other  | 
4,412  | 
 
  | 
   | 
(5,860  | 
)  | 
   | 
3,969  | 
 
  | 
   | 
(7,872  | 
)  | 
 
   | 
72,995  | 
 
  | 
   | 
18,448  | 
 
  | 
   | 
7,109  | 
 
  | 
   | 
(11,833  | 
)  | 
 
Eliminate Liberty Broadband  | 
(11,791  | 
)  | 
   | 
(4,560  | 
)  | 
   | 
(3,140  | 
)  | 
   | 
3,961  | 
 
  | 
 
   | 
$  | 
61,204  | 
 
  | 
   | 
13,888  | 
 
  | 
   | 
3,969  | 
 
  | 
   | 
(7,872  | 
)  | 
 
  
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| Reconciliation of Assets from Segment to Consolidated | 
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   | 
   | 
March 31, 2018  | 
 
   | 
   | 
Total  | 
   | 
Investments  | 
   | 
Capital  | 
 
   | 
   | 
assets  | 
   | 
in affiliates  | 
   | 
expenditures  | 
 
   | 
   | 
amounts in thousands  | 
 
GCI Holdings  | 
   | 
$  | 
3,555,357  | 
 
  | 
   | 
—  | 
 
  | 
   | 
5,777  | 
 
  | 
 
Liberty Broadband  | 
   | 
11,957,547  | 
 
  | 
   | 
11,866,434  | 
 
  | 
   | 
14  | 
 
  | 
 
Corporate and other  | 
   | 
6,029,394  | 
 
  | 
   | 
112,975  | 
 
  | 
   | 
723  | 
 
  | 
 
   | 
   | 
21,542,298  | 
 
  | 
   | 
11,979,409  | 
 
  | 
   | 
6,514  | 
 
  | 
 
Eliminate Liberty Broadband  | 
   | 
(11,957,547  | 
)  | 
   | 
(11,866,434  | 
)  | 
   | 
(14  | 
)  | 
 
Consolidated GCI Liberty  | 
   | 
$  | 
9,584,751  | 
 
  | 
   | 
112,975  | 
 
  | 
   | 
6,500  | 
 
  | 
 
  
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| Reconciliation of Adjusted OIBDA to Operating Income and Earnings (Loss) from Continuing Operations | 
The following table provides a reconciliation of segment Adjusted OIBDA to operating income and earnings (loss) from continuing operations before income taxes: 
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   | 
Three months ended March 31,  | 
 
   | 
2018  | 
   | 
2017  | 
 
   | 
amounts in thousands  | 
 
Consolidated segment Adjusted OIBDA  | 
$  | 
13,888  | 
 
  | 
   | 
(7,872  | 
)  | 
 
Stock‑based compensation  | 
(5,236  | 
)  | 
   | 
(2,726  | 
)  | 
 
Depreciation and amortization  | 
(16,021  | 
)  | 
   | 
(753  | 
)  | 
 
Operating income  | 
(7,369  | 
)  | 
   | 
(11,351  | 
)  | 
 
Interest expense  | 
(8,248  | 
)  | 
   | 
—  | 
 
  | 
 
Share of earnings (loss) of affiliates, net  | 
(2,492  | 
)  | 
   | 
1,723  | 
 
  | 
 
Realized and unrealized gains (losses) on financial instruments, net  | 
(71,481  | 
)  | 
   | 
737,552  | 
 
  | 
 
Other, net  | 
1,697  | 
 
  | 
   | 
209  | 
 
  | 
 
Earnings (loss) from continuing operations before income taxes  | 
$  | 
(87,893  | 
)  | 
   | 
728,133  | 
 
  | 
 
  
 
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