CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Sep. 29, 2013	Dec. 31, 2012
Statement Of Financial Position [Abstract]
Allowance for accounts receivable	$ 721	$ 811
Accumulated depreciation	$ 239,900	$ 240,693
Preferred stock, without par value	$ 0	$ 0
Preferred stock, shares authorized	25,000,000	25,000,000
Preferred stock, shares issued	0	0
Common stock, without par value	$ 0	$ 0
Common stock, shares authorized	75,000,000	75,000,000
Common stock, shares issued	55,693,235	55,263,082
Common stock held in treasury, shares	22,029,923	21,829,954