CONDENSED CONSOLIDATED STATEMENTS OF FINANCIAL POSITION (Parenthetical) (USD $) In Thousands, except Per Share data	Jul. 02, 2011	Dec. 31, 2010	Jul. 03, 2010
Trade accounts receivable, allowances (in dollars)	$ 1,661	$ 1,531	$ 1,879
Treasury stock, shares	71	69	69
Common Stock
Common Stock, par value (in dollars per share)	$ 0.6944	$ 0.6944	$ 0.6944
Common Stock, shares authorized	120,000	120,000	120,000
Common Stock, shares issued	36,890	36,057	36,517
Class B common stock
Common Stock, par value (in dollars per share)	$ 0.6944	$ 0.6944	$ 0.6944
Common Stock, shares authorized	40,000	40,000	40,000
Common Stock, shares issued	21,040	20,466	20,488