Liberty Broadband Corporation Quarterly report pursuant to Section 13 or 15(d)

Information About the Company's Operating Segments (Performance Measures) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Revenue	$ 210,146	$ 5,493	$ 504,840	$ 15,639
Adjusted OIBDA	50,740	(5,277)	136,352	(20,071)
Operating Segments
Segment Reporting Information [Line Items]
Revenue	213,664	8,923	523,520	25,282
Adjusted OIBDA	48,542	(8,623)	135,938	(32,333)
Operating Segments \| GCI Holdings
Segment Reporting Information [Line Items]
Revenue	205,047	0	489,620	0
Adjusted OIBDA	57,945	0	156,608	0
Operating Segments \| Liberty Broadband
Segment Reporting Information [Line Items]
Revenue	3,518	3,430	18,680	9,643
Adjusted OIBDA	(2,198)	(3,346)	(414)	(12,262)
Operating Segments \| Corporate and other
Segment Reporting Information [Line Items]
Revenue	5,099	5,493	15,220	15,639
Adjusted OIBDA	(7,205)	(5,277)	(20,256)	(20,071)
Consolidation, Eliminations
Segment Reporting Information [Line Items]
Revenue	(3,518)	(3,430)	(18,680)	(9,643)
Adjusted OIBDA	$ 2,198	$ 3,346	$ 414	$ 12,262