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

Information About GCI Liberty's Operating Segments (Other Information) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total assets	$ 9,584,751	$ 6,172,213
Investment accounted for using the equity method	112,975	$ 114,655
Capital expenditures	6,500
Operating Segments
Segment Reporting Information [Line Items]
Total assets	21,542,298
Investment accounted for using the equity method	11,979,409
Capital expenditures	6,514
Operating Segments \| GCI Holdings
Segment Reporting Information [Line Items]
Total assets	3,555,357
Investment accounted for using the equity method	0
Capital expenditures	5,777
Operating Segments \| Liberty Broadband
Segment Reporting Information [Line Items]
Total assets	11,957,547
Investment accounted for using the equity method	11,866,434
Capital expenditures	14
Operating Segments \| Corporate and other
Segment Reporting Information [Line Items]
Total assets	6,029,394
Investment accounted for using the equity method	112,975
Capital expenditures	723
Consolidation, Eliminations
Segment Reporting Information [Line Items]
Total assets	(11,957,547)
Investment accounted for using the equity method	(11,866,434)
Capital expenditures	$ (14)