Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data	Oct. 02, 2011	Dec. 31, 2010
Current Assets
Allowance for doubtful debts	$ 1,017	$ 1,269
Accumulated depreciation on property, plant and equipment	$ 242,713	$ 244,662
Shareholders' Equity
Preferred stock, without par value
Preferred stock, shares authorized	25,000,000	25,000,000
Preferred stock, shares issued
Common stock, without par value
Common stock, shares authorized	75,000,000	75,000,000
Common stock, shares issued	54,789,426	54,517,560
Cost of common stock held in treasury - Note K	20,467,363	20,320,759