Goodwill and other intangible assets (Details) (USD $) In Thousands, unless otherwise specified	Sep. 29, 2013	Dec. 30, 2012
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill	$ 2,859,310	$ 2,846,869
Customer Relationships [Member]
Goodwill, indefinite-lived intangible assets, and amortizable intangible assets
Finite-Lived Intangible Assets, Gross	321,321	313,567
Finite-Lived Intangible Assets, Accumulated Amortization	217,795	197,300
Other [Member]
Goodwill, indefinite-lived intangible assets, and amortizable intangible assets
Finite-Lived Intangible Assets, Gross	47,939	56,965
Finite-Lived Intangible Assets, Accumulated Amortization	23,020	23,931
Mastheads and trade names [Member]
Goodwill, indefinite-lived intangible assets, and amortizable intangible assets
Accumulated Amortization	0	0
Indefinite-Lived Intangible Assets (Excluding Goodwill)	94,490	95,308
Television station FCC licenses [Member]
Goodwill, indefinite-lived intangible assets, and amortizable intangible assets
Accumulated Amortization	0	0
Indefinite-Lived Intangible Assets (Excluding Goodwill)	255,304	255,304
Goodwill [Member]
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill	2,859,310	2,846,869
Goodwill, indefinite-lived intangible assets, and amortizable intangible assets
Accumulated Amortization	$ 0	$ 0