Basis Of Presentation And Significant Accounting Policies (Details) $ / shares in Units, $ in Thousands			3 Months Ended		6 Months Ended
	Aug. 02, 2017	May 08, 2017 USD ($) $ / shares	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)		Jun. 30, 2016 USD ($)
Investment Holdings [Line Items]
Operating revenues			$ 469,517	$ 479,796	$ 909,427	[1]	$ 948,268	[1]
Operating profit			18,326	56,206	3,094	[1],[2]	86,198	[1],[2]
Dreamcatcher Stations | Variable Interest Entity, Primary Beneficiary
Investment Holdings [Line Items]
Operating revenues			18,000	18,000	35,000		35,000
Operating profit			$ 4,000	$ 4,000	$ 6,000		$ 7,000
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
Contract Termination Fee		$ 135,500
Contract Termination Fee When Stockholder Merger Vote Not Obtained		38,500
Contract Termination Fees, Sinclair Cost Reimbursement		$ 10,000
Grace Period After Contact Termination, Not Terminated by Company, Before Obtaining New Bid Without Termination Fee		12 months
Sinclair Merger | Sinclair
Investment Holdings [Line Items]
Common Stock, Par or Stated Value Per Share | $ / shares		$ 0.01
Subsequent Event
Investment Holdings [Line Items]
Hart-Scott-Rodino Antitrust Improvement Act of 1976 Waiting Period	30 days

[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.