Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 27, 2015	Dec. 28, 2014	Sep. 28, 2014
Allowance for doubtful accounts	$ 1,777	$ 1,330	$ 1,490
Common Stock [Member]
Common stock, par value	$ 1.00	$ 1.00	$ 1.00
Common stock, shares authorized	30,000,000	30,000,000	30,000,000
Common stock, shares issued	10,203,821	10,203,821	10,203,821
Treasury stock, shares	3,062,374	3,062,374	3,062,374
Class B Common Stock [Member]
Common stock, par value	$ 1.00	$ 1.00	$ 1.00
Common stock, shares authorized	10,000,000	10,000,000	10,000,000
Common stock, shares issued	2,778,896	2,757,976	2,757,976
Treasury stock, shares	628,114	628,114	628,114