Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
Apr. 04, 2015	Mar. 29, 2014
Earnings Per Share
Net income	$ 6,378	$ 8,110
Shares used in computing basic earnings per share	42,412,000	43,081,000
Effect of dilutive securities:
Stock options and other stock-based awards (in shares)	737,000	975,000
Shares used in computing diluted earnings per share	43,149,000	44,056,000
Earnings per share:
Basic (in dollars per share)	$ 0.15us-gaap_EarningsPerShareBasic	$ 0.19us-gaap_EarningsPerShareBasic
Diluted (in dollars per share)	$ 0.15us-gaap_EarningsPerShareDiluted	$ 0.18us-gaap_EarningsPerShareDiluted
Shares excluded from computation of diluted earning per share	100,000	200,000

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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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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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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