Basis Of Presentation And Significant Accounting Policies (Details)			3 Months Ended		9 Months Ended		12 Months Ended
		Aug. 09, 2018 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	May 08, 2018 USD ($) television_station	Dec. 31, 2016 USD ($)
Investment Holdings [Line Items]
Operating revenues	[1]		$ 498,008,000	$ 450,533,000	$ 1,431,001,000	$ 1,359,960,000
Costs and Expenses			460,884,000	479,985,000	1,108,526,000	1,397,726,000
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification				6,000,000		17,000,000	$ 23,000,000
Restricted cash and cash equivalents			16,607,000	17,566,000	$ 16,607,000	17,566,000	17,566,000		$ 17,566,000
Deferred Revenue and Other LT Liability, Useful Lives, Spectrum					30 years
Operating profit	[1],[2]		37,124,000	(29,452,000)	$ 322,475,000	(37,766,000)
Federal Communications Commission Regulation, Proceeds Received From Auction							191,000,000
Dreamcatcher Stations
Investment Holdings [Line Items]
Federal Communications Commission Regulation, Proceeds Received From Auction				21,000,000			26,000,000
Dreamcatcher Stations | Variable Interest Entity, Primary Beneficiary
Investment Holdings [Line Items]
Operating revenues			20,000,000	17,000,000	57,000,000	52,000,000
Operating profit			4,000,000	3,000,000	12,000,000	8,000,000
Corporate and Other
Investment Holdings [Line Items]
Operating revenues	[1]		3,389,000	3,226,000	9,263,000	10,559,000
Operating profit	[1],[2]		(30,171,000)	(28,095,000)	(76,439,000)	(106,641,000)
Barter
Investment Holdings [Line Items]
Operating revenues			7,000,000	$ 7,000,000	21,000,000	$ 21,000,000
Costs and Expenses			7,000,000		21,000,000
Program rights			51,000,000		51,000,000		45,000,000
Program Rights Obligations			$ 51,000,000		$ 51,000,000		$ 45,000,000
Sinclair Merger | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Investment Holdings [Line Items]
Television stations, Tribune to sell upon close of merger | television_station								7
Disposal Group, Including Discontinued Operation, Consideration								$ 910,000,000
Fox Purchase Agreement
Investment Holdings [Line Items]
Contract Termination Fee		$ 0

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

[2] (2)Operating profit (loss) for each segment excludes income and loss on equity investments, interest and dividend income, interest expense, pension and other postretirement period benefit cost (credit), non-operating items, reorganization costs and income taxes.