Goodwill and Other Intangible Assets - Intangible Assets and Goodwill (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill	$ 2,605,863	$ 2,596,863
Goodwill, accumulated amortization	0	0
Total indefinite-live and amortizable intangible assets	1,726,770	1,645,035
Total indefinite-live and amortizable intangible assets, accumulated amortization	(127,646)	(118,958)
Retransmission agreements
Goodwill and Intangible Assets Disclosure [Line Items]
Amortizable intangible assets	133,847	121,594
Amortizable intangible assets, accumulated amortization	(83,730)	(79,274)
Network affiliation agreements
Goodwill and Intangible Assets Disclosure [Line Items]
Amortizable intangible assets	126,494	110,390
Amortizable intangible assets, accumulated amortization	(34,383)	(30,802)
Other
Goodwill and Intangible Assets Disclosure [Line Items]
Amortizable intangible assets	28,864	28,865
Amortizable intangible assets, accumulated amortization	(9,533)	(8,882)
Television and radio station FCC licenses
Goodwill and Intangible Assets Disclosure [Line Items]
Indefinite-lived intangibles	1,437,565	1,384,186
Total indefinite-live and amortizable intangible assets, accumulated amortization	$ 0	$ 0