Basis Of Presentation And Significant Accounting Policies (Details) $ / shares in Units, $ in Thousands						3 Months Ended		6 Months Ended		12 Months Ended
		Oct. 18, 2017	Sep. 15, 2017	Jul. 06, 2017	May 08, 2017 $ / shares	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	May 08, 2018 USD ($) television_station	Apr. 24, 2018 television_station	Feb. 20, 2018 television_station	Dec. 31, 2016 USD ($)
Investment Holdings [Line Items]
Operating revenues	[1]					$ 489,358	$ 469,517	$ 932,993	$ 909,427
Costs and Expenses						391,292	456,864	647,642	917,741
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification							6,000		11,000	$ 23,000
Restricted cash and cash equivalents						16,607	17,566	$ 16,607	17,566	17,566				$ 17,566
Deferred Revenue and Other LT Liability, Useful Lives, Spectrum								30 years
Operating profit	[1],[2]					98,066	12,653	$ 285,351	(8,314)
Federal Communications Commission Regulation, Proceeds Received From Auction										191,000
Corporate and Other
Investment Holdings [Line Items]
Operating revenues	[1]					2,941	3,456	5,874	7,333
Operating profit	[1],[2]					(21,701)	(37,566)	(46,268)	(78,546)
Barter
Investment Holdings [Line Items]
Operating revenues						7,000	7,000	14,000	14,000
Costs and Expenses						7,000		14,000
Program rights						35,000		35,000		45,000
Program Rights Obligations						35,000		35,000		45,000
Dreamcatcher Stations
Investment Holdings [Line Items]
Federal Communications Commission Regulation, Proceeds Received From Auction										$ 26,000
Dreamcatcher Stations | Variable Interest Entity, Primary Beneficiary
Investment Holdings [Line Items]
Operating revenues						19,000	18,000	37,000	35,000
Operating profit						$ 5,000	$ 4,000	$ 8,000	$ 6,000
Sinclair Merger
Investment Holdings [Line Items]
Business Combination, Common Stock Cash Value Per Share Conversion | $ / shares					$ 35.00
Business Combination, Consideration Transferred, Common Stock Exchange Ratio					0.2300
FCC Transaction Review Period				180 days
FCC Transaction Review Period, Pause		15 days
Television Markets, Sinclair Proposes to Own Duopoly | television_station													3
Television Markets, Sinclair Proposes to Divest | television_station												15	11
Television Stations, Sinclair proposes assignment of license or transfer of control | television_station												11
Department of Justice, Days Notice			10 days
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
Sinclair Merger | Sinclair
Investment Holdings [Line Items]
Common Stock, Par or Stated Value Per Share | $ / shares					$ 0.01

[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, non-operating items, reorganization costs and income taxes.