Information About the Company's Operating Segments - (Adjusted OIBDA) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Adjusted OIBDA	$ 68,359	$ 61,399	$ 145,076	$ 100,746
Operating Segments
Segment Reporting Information [Line Items]
Adjusted OIBDA	60,952	57,225	132,688	93,455
Operating Segments | GCI Holdings
Segment Reporting Information [Line Items]
Adjusted OIBDA	78,045	66,121	164,440	110,592
Operating Segments | Liberty Broadband
Segment Reporting Information [Line Items]
Adjusted OIBDA	(7,407)	(4,174)	(12,388)	(7,291)
Operating Segments | Corporate and other
Segment Reporting Information [Line Items]
Adjusted OIBDA	(9,686)	(4,722)	(19,364)	(9,846)
Consolidation, Eliminations
Segment Reporting Information [Line Items]
Adjusted OIBDA	$ 7,407	$ 4,174	$ 12,388	$ 7,291