Facility consolidation charges (Details Textual) (USD $)	3 Months Ended		6 Months Ended
	Jun. 24, 2012	Jun. 26, 2011	Jun. 24, 2012	Jun. 26, 2011
Facility Consolidation Charges (Textual) [Abstract]
Asset impairment charges, pre-tax	$ 5,097,000	$ 6,394,000	$ 9,885,000	$ 14,050,000
Publishing [Member] | Operations [Member] | Property Plant And Equipment [Member]
Facility Consolidation Charges (Textual) [Abstract]
Asset impairment charges, pre-tax	5,100,000	6,400,000	9,900,000	14,100,000
Asset impairment charges, after-tax	$ 3,100,000	$ 3,900,000	$ 6,000,000	$ 8,500,000
Asset impairment charges, per share	$ 0.01	$ 0.02	$ 0.03	$ 0.03