Information About the Company's Operating Segments - (Other Information) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total assets	$ 12,805,686	$ 11,356,020
Investments in affiliates	157,484	$ 167,643
Capital expenditures	107,247
Operating Segments
Segment Reporting Information [Line Items]
Total assets	25,667,375
Investments in affiliates	12,607,909
Capital expenditures	107,289
Operating Segments | GCI Holdings
Segment Reporting Information [Line Items]
Total assets	3,184,250
Investments in affiliates	528
Capital expenditures	106,370
Operating Segments | Liberty Broadband
Segment Reporting Information [Line Items]
Total assets	12,861,689
Investments in affiliates	12,450,425
Capital expenditures	42
Operating Segments | Corporate and other
Segment Reporting Information [Line Items]
Total assets	9,621,436
Investments in affiliates	156,956
Capital expenditures	877
Consolidation, Eliminations
Segment Reporting Information [Line Items]
Total assets	(12,861,689)
Investments in affiliates	(12,450,425)
Capital expenditures	$ (42)