Basis of Presentation and Significant Accounting Policies Dreamcatcher (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
	Dec. 27, 2013	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Variable Interest Entity [Line Items]
Federal Communications Commission Regulation, Proceeds Received From Auction										$ 191,000
Total operating revenues		$ 488,999	$ 450,533	$ 469,517	$ 439,910	$ 529,624	$ 470,038	$ 479,796	$ 468,472	1,848,959	[1]	$ 1,947,930	[1]	$ 1,801,967	[1]
Total operating (loss) profit		$ 129,123	$ (23,749)	$ 18,326	$ (15,232)	$ 113,206	$ 234,170	$ 56,206	$ 29,992	108,468	[1]	433,574	[1]	(269,335)	[1]
Dreamcatcher Stations
Variable Interest Entity [Line Items]
Federal Communications Commission Regulation, Proceeds Received From Auction										26,000
Dreamcatcher | Dreamcatcher Stations
Variable Interest Entity [Line Items]
Business Combination, Consideration Transferred	$ 27,000
Variable Interest Entity, Primary Beneficiary | Dreamcatcher Stations
Variable Interest Entity [Line Items]
Total operating revenues										72,000		73,000		65,000
Total operating (loss) profit										$ 12,000		$ 16,000		$ 12,000
Variable Interest Entity, Primary Beneficiary | Dreamcatcher
Variable Interest Entity [Line Items]
Variable Interest Entity, Financial or Other Support, Amount	$ 200

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