Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 29, 2012	Oct. 01, 2011	Sep. 29, 2012	Oct. 01, 2011
Income Taxes
Income tax expense	$ 17,054,000	$ 2,976,000	$ 17,131,000	$ 13,894,000
Income tax rate (as a percent)	63.00%	20.90%	27.60%	38.00%
Gross unrecognized tax benefits	4,300,000		4,300,000
Gross unrecognized tax benefits which would affect the effective tax rate if recognized	4,100,000		4,100,000
Net decrease in uncertain tax positions			6,900,000
Reductions for uncertain tax positions that was determined to be effectively settled			8,400,000
Increase in uncertain tax positions in current year			$ 1,500,000