Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 28, 2018	Dec. 28, 2017
Accounts and notes receivable, reserves	$ 193	$ 161
Preferred Stock, par (in dollars per share)	$ 1	$ 1
Preferred Stock, authorized	1,000,000	1,000,000
Preferred Stock, issued	0	0
Cost of Common Stock in treasury, shares	3,145,440	3,335,745
Common Stock [Member]
Common Stock, par (in dollars per share)	$ 1	$ 1
Common Stock, authorized	50,000,000	50,000,000
Common Stock, issued	22,668,528	22,655,517
Class B Common Stock [Member]
Common Stock, par (in dollars per share)	$ 1	$ 1
Common Stock, authorized	33,000,000	33,000,000
Common Stock, issued	8,520,985	8,533,996
Common Stock, outstanding	8,520,985	8,533,996