Summary of Quarterly Financial Data (unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
Dec. 31, 2011	Oct. 01, 2011	Jul. 02, 2011	Apr. 02, 2011	Jan. 01, 2011	Oct. 02, 2010	Jul. 03, 2010	Apr. 03, 2010	Dec. 31, 2011	Jan. 01, 2011	Jan. 02, 2010
Summary of Quarterly Financial Data (unaudited) [Abstract]
Net sales	$ 189,073	$ 199,600	$ 161,462	$ 193,068	$ 148,668	$ 160,103	$ 138,952	$ 157,953	$ 743,203	$ 605,676	$ 544,202
Gross profit	118,978	125,762	102,504	123,101	93,725	99,989	86,465	98,084	470,345	378,263	335,460
Operating income	19,970	26,459	17,626	26,398	11,477	16,780	9,937	14,189	90,453	52,383	20,673
Net income	$ 15,370	$ 17,236	$ 11,289	$ 16,583	$ 7,118	$ 10,488	$ 6,202	$ 7,760	$ 60,478	$ 31,568	$ 35,552
Net income per share - diluted	$ 0.27	$ 0.31	$ 0.20	$ 0.30	$ 0.13	$ 0.19	$ 0.11	$ 0.14	$ 1.07	$ 0.57	$ 0.77

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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