CONDENSED BALANCE SHEETS (Parenthetical) (USD $)	Jun. 29, 2013	Dec. 31, 2012
Treasury stock, shares	4,299,434	4,299,434
Nonvoting Common Stock [Member]
Common Stock, par value per share	$ 1	$ 1
Common Stock, shares authorized	50,000	50,000
Common Stock, shares issued	0	0
Voting Common Stock [Member]
Common Stock, par value per share	$ 1	$ 1
Common Stock, shares authorized	40,000,000	40,000,000
Common Stock, shares issued	23,640,804	23,562,422
Common Stock, shares outstanding	19,341,370	19,262,988