Goodwill and other intangible assets (Details) (USD $) In Thousands, unless otherwise specified	Sep. 23, 2012	Dec. 25, 2011
Customer Relationships [Member]
Goodwill, indefinite-lived intangible assets, and amortizable intangible assets
Gross	$ 311,249	$ 298,437
Accumulated Amortization	189,669	169,499
Other [Member]
Goodwill, indefinite-lived intangible assets, and amortizable intangible assets
Gross	50,668	43,624
Accumulated Amortization	23,338	18,834
Mastheads and trade names [Member]
Goodwill, indefinite-lived intangible assets, and amortizable intangible assets
Gross	95,348	93,163
Television station FCC licenses [Member]
Goodwill, indefinite-lived intangible assets, and amortizable intangible assets
Gross	255,304	255,304
Goodwill [Member]
Goodwill, indefinite-lived intangible assets, and amortizable intangible assets
Gross	$ 2,943,641	$ 2,864,885