Goodwill and other intangible assets - Goodwill, Indefinite-Lived Intangible Assets, and Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 28, 2014
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill	$ 4,067,529	$ 3,919,726	$ 3,914,771
Total intangible assets, gross	7,405,377	7,205,495
Intangible assets, accumulated amortization	(324,416)	(220,662)
Total intangible assets, net	7,080,961	6,984,833
Customer relationships
Goodwill and Intangible Assets Disclosure [Line Items]
Finite-Lived Intangible Assets, Gross	929,852	903,652
Finite-Lived Intangible Assets, Accumulated Amortization	(210,691)	(145,398)
Finite-Lived Intangible Assets, Net	719,161	758,254
Other
Goodwill and Intangible Assets Disclosure [Line Items]
Finite-Lived Intangible Assets, Gross	290,875	265,148
Finite-Lived Intangible Assets, Accumulated Amortization	(113,725)	(75,264)
Finite-Lived Intangible Assets, Net	177,150	189,884
Television station FCC licenses
Goodwill and Intangible Assets Disclosure [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill)	1,191,950	1,191,950
Intangible assets, accumulated amortization	0	0
Trade names
Goodwill and Intangible Assets Disclosure [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill)	925,171	925,019
Intangible assets, accumulated amortization	0	0
Goodwill
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill	4,067,529	3,919,726
Intangible assets, accumulated amortization	$ 0	$ 0