CONDENSED CONSOLIDATED BALANCE SHEET (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2013	Dec. 30, 2012
Trade receivables, allowance	$ 6,355	$ 5,920
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Treasury stock, shares	460,487	6,034
Common Class A
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	61,804,320	61,098,820
Common Class B
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares issued	24,800,962	24,800,962