CONDENSED CONSOLIDATED STATEMENTS OF FINANCIAL POSITION (Parenthetical) (USD $) In Thousands, except Per Share data	Oct. 01, 2011	Dec. 31, 2010	Oct. 02, 2010
Trade accounts receivable, allowances (in dollars)	$ 2,621	$ 1,531	$ 2,949
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	36,807	36,057	36,459
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	21,032	20,466	20,476