Information About the Company's Operating Segments (Adjusted OIBDA) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Adjusted OIBDA	$ 39,347	$ 14,088
Operating Segments
Segment Reporting Information [Line Items]
Adjusted OIBDA	36,230	18,648
Operating Segments | GCI Holdings
Segment Reporting Information [Line Items]
Adjusted OIBDA	44,471	19,748
Operating Segments | Liberty Broadband
Segment Reporting Information [Line Items]
Adjusted OIBDA	(3,117)	4,560
Operating Segments | Corporate and other
Segment Reporting Information [Line Items]
Adjusted OIBDA	(5,124)	(5,660)
Consolidation, Eliminations
Segment Reporting Information [Line Items]
Adjusted OIBDA	$ 3,117	$ (4,560)