Goodwill and Other Intangible Assets - Summary of other intangible assets (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Carrying amount:
Total carrying amount	$ 331,467	$ 331,467
Accumulated amortization:
Total accumulated amortization	(78,616)	(67,386)
Net amortizable intangible assets	252,851	264,081
Total other intangible assets	456,666	467,896
Indefinite-lived intangible assets - FCC licenses
Accumulated amortization:
Indefinite-lived intangible assets — FCC licenses	203,815	203,815
Television network affiliation relationships
Carrying amount:
Total carrying amount	248,444	248,444
Accumulated amortization:
Total accumulated amortization	(43,449)	(37,019)
Customer lists and advertiser relationships
Carrying amount:
Total carrying amount	56,100	56,100
Accumulated amortization:
Total accumulated amortization	(26,820)	(24,380)
Other
Carrying amount:
Total carrying amount	26,923	26,923
Accumulated amortization:
Total accumulated amortization	$ (8,347)	$ (5,987)