Basis Of Presentation And Significant Accounting Policies - Disaggregated Revenue (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017		Sep. 30, 2018	Sep. 30, 2017
Operating revenues	[1]	$ 498,008	$ 450,533		$ 1,431,001	$ 1,359,960
Television and Entertainment
Operating revenues		494,619	447,307	[2]	1,421,738	1,349,401	[2]
Advertising | Television and Entertainment
Operating revenues		327,248	295,130	[2]	909,118	899,701	[2]
Retransmission revenues | Television and Entertainment
Operating revenues		116,625	104,587	[2]	351,952	303,800	[2]
Carriage fees | Television and Entertainment
Operating revenues		40,069	30,930	[2]	122,546	96,407	[2]
Barter/trade | Television and Entertainment
Operating revenues	[3]	2,660	9,559	[2]	7,142	28,052	[2]
Other revenue | Television and Entertainment
Operating revenues		$ 8,017	$ 7,101	[2]	$ 30,980	$ 21,441	[2]

[1] (1)See Note 2 for the disclosures of operating revenues and operating loss included in discontinued operations for the historical periods.

[2] (1)Prior period amounts have not been adjusted under the modified retrospective method.

[3] (2)For the three and nine months ended September 30, 2017, barter revenue totaled $7 million and $21 million, respectively.