Note 9 - Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Net income	$ 48,638	$ 27,152	$ 87,530	$ 46,441
Basic (in shares)	22,822	22,528	22,785	22,483
Effect of dilutive securities (in shares)	201	146	220	164
Diluted (in shares)	23,023	22,674	23,005	22,647
Earnings Per Share:
Basic earnings per share (in dollars per share)	$ 2.13	$ 1.21	$ 3.84	$ 2.07
Diluted earnings per share (in dollars per share)	$ 2.11	$ 1.20	$ 3.80	$ 2.05

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

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The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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