Goodwill And Other Intangible Assets - (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Indefinite-lived Intangible Assets [Line Items]
Other intangible assets not subject to amortization	$ 755,100	$ 755,100
Total other intangible assets, net (excluding goodwill)	1,571,957	1,613,665
Goodwill	3,229,238	3,228,988
Total goodwill and other intangible assets	4,801,195	4,842,653
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	1,589,012	1,588,750
Intangible assets, accumulated amortization	(772,155)	(730,185)
Intangible assets subject to amortization, net	816,857	858,565
FCC Licenses
Indefinite-lived Intangible Assets [Line Items]
Other intangible assets not subject to amortization	740,300	740,300
Trade Names
Indefinite-lived Intangible Assets [Line Items]
Other intangible assets not subject to amortization	14,800	14,800
Affiliate Relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	212,000	212,000
Intangible assets, accumulated amortization	(69,563)	(66,250)
Intangible assets subject to amortization, net	$ 142,437	145,750
Affiliate Relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	16 years
Affiliate Relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	16 years
Advertiser relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	$ 168,000	168,000
Intangible assets, accumulated amortization	(110,250)	(105,000)
Intangible assets subject to amortization, net	$ 57,750	63,000
Advertiser relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	8 years
Advertiser relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	8 years
Network Affiliation Agreements
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	$ 362,000	362,000
Intangible assets, accumulated amortization	(185,740)	(175,337)
Intangible assets subject to amortization, net	$ 176,260	186,663
Network Affiliation Agreements | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	5 years
Network Affiliation Agreements | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	16 years
Retransmission Consent Agreements
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	$ 830,100	830,100
Intangible assets, accumulated amortization	(399,543)	(377,033)
Intangible assets subject to amortization, net	$ 430,557	453,067
Retransmission Consent Agreements | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	7 years
Retransmission Consent Agreements | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	12 years
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, gross	$ 16,912	16,650
Intangible assets, accumulated amortization	(7,059)	(6,565)
Intangible assets subject to amortization, net	$ 9,853	$ 10,085
Other Intangible Assets | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	5 years
Other Intangible Assets | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	15 years