CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 27, 2016	Dec. 27, 2015
Trade receivables, allowance	$ 4,497	$ 4,451
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Treasury stock, shares	5,249,454	1,652,165
Common Class A
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	59,467,435	58,782,535
Common Class B
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares issued	24,431,962	24,431,962