Goodwill and Other Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Intangible assets:
Intangible assets, Gross	$ 1,661,900	$ 1,524,101
Accumulated Amortization	(552,228)	(431,419)
Intangible assets, Net	1,109,672	1,092,682	$ 1,262,664
Acquired network distribution [Member]
Intangible assets:
Intangible assets, Gross	747,941	717,834
Accumulated Amortization	(278,657)	(232,856)
Intangible assets, Net	469,284	484,978
Customer and advertiser lists [Member]
Intangible assets:
Intangible assets, Gross	233,451	209,314
Accumulated Amortization	(117,134)	(93,232)
Intangible assets, Net	116,317	116,082
Copyrights and other trade names [Member]
Intangible assets:
Intangible assets, Gross	422,575	362,236
Accumulated Amortization	(98,058)	(61,286)
Intangible assets, Net	324,517	300,950
Broadcast licenses [Member]
Intangible assets:
Intangible assets, Gross	137,773	114,832
Accumulated Amortization	(16,058)	(7,861)
Intangible assets, Net	121,715	106,971
Acquired rights and other [Member]
Intangible assets:
Intangible assets, Gross	120,160	119,885
Accumulated Amortization	(42,321)	(36,184)
Intangible assets, Net	$ 77,839	$ 83,701