Goodwill and Other Intangible Assets - Intangible Assets and Goodwill (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill	$ 2,579,417	$ 2,579,417
Goodwill, Accumulated Amortization	0	0
Total indefinite-live and amortizable intangible assets	1,361,389	1,361,389
Total indefinite-live and amortizable intangible assets, accumulated amortization	(82,722)	(66,550)
Retransmission agreements
Goodwill and Intangible Assets Disclosure [Line Items]
Amortizable intangible assets	110,191	110,191
Amortizable intangible assets, accumulated amortization	(58,586)	(47,280)
Network affiliation agreements
Goodwill and Intangible Assets Disclosure [Line Items]
Amortizable intangible assets	43,485	43,485
Amortizable intangible assets, accumulated amortization	(18,139)	(14,445)
Other
Goodwill and Intangible Assets Disclosure [Line Items]
Amortizable intangible assets	15,763	15,763
Amortizable intangible assets, accumulated amortization	(5,997)	(4,825)
Television station FCC licenses
Goodwill and Intangible Assets Disclosure [Line Items]
Indefinite-lived intangibles	1,191,950	1,191,950
Total indefinite-live and amortizable intangible assets, accumulated amortization	$ 0	$ 0