Acquisition (Preliminary Purchase Price Allocation) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 09, 2018
Business Acquisition [Line Items]
Goodwill	$ 844,182	$ 844,182
HoldCo | GCI LLC
Business Acquisition [Line Items]
Cash and cash equivalents including restricted cash			$ 147,957
Receivables			171,014
Property and equipment			1,211,392
Goodwill			966,044
Intangible assets not subject to amortization			572,500
Intangible assets subject to amortization			468,737
Other assets			83,422
Deferred revenue			(92,561)
Debt, including capital leases			(1,632,002)
Other liabilities			(171,151)
Deferred income tax liabilities			(276,683)
Non-controlling interest			(7,000)
Net assets acquired including goodwill, less noncontrolling interest			$ 1,441,669