Note 9 - Earnings Per Share (Details) - Computation of Basic and Diluted Earnings Per Share under the Two-class Method (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012
Computation of Basic and Diluted Earnings Per Share under the Two-class Method [Abstract]
Net income as reported	$ 26,990	$ 22,778	$ 68,432	$ 63,304
Less: Distributed earnings available to participating securities	(3)	(9)	(21)	(21)
Less: Undistributed earnings available to participating securities		(19)	(17)	(102)
Numerator for basic earnings per share —
Undistributed and distributed earnings available to common shareholders	26,987	22,750	68,394	63,181
Add: Undistributed earnings allocated to participating securities		19	17	102
Less: Undistributed earnings reallocated to participating securities		(19)	(17)	(100)
Numerator for diluted earnings per share —
Undistributed and distributed earnings available to common shareholders	$ 26,987	$ 22,750	$ 68,394	$ 63,183
Denominator for basic earnings per share —
Weighted-average shares (in Shares)	22,428	21,923	22,274	21,770
Effect of dilutive securities:
Common stock equivalents (in Shares)	197	239	223	285
Denominator for diluted earnings per share — (in Shares)	22,625	22,162	22,497	22,055
Basic earnings per share (in Dollars per share)	$ 1.20	$ 1.04	$ 3.07	$ 2.90
Diluted earnings per share (in Dollars per share)	$ 1.19	$ 1.03	$ 3.04	$ 2.87