Goodwill and Intangible Assets (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Schedule of Goodwill And Intangible Assets [Line Items]
Goodwill impairment	$ 0	$ 147,431
Corporate and other
Schedule of Goodwill And Intangible Assets [Line Items]
Goodwill impairment	0	0
Accumulated goodwill impairment losses	55,700
GCI Holdings
Schedule of Goodwill And Intangible Assets [Line Items]
Goodwill impairment		147,400
Accumulated goodwill impairment losses	147,400
GCI Holdings | Wireless License
Schedule of Goodwill And Intangible Assets [Line Items]
Impairment loss on indefinite-lived intangibles	$ 157,000
GCI Holdings | Cable certificates
Schedule of Goodwill And Intangible Assets [Line Items]
Impairment loss on indefinite-lived intangibles		$ 65,000