Note 8 - 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		6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014	Jun. 29, 2013
Computation of Basic and Diluted Earnings Per Share under the Two-class Method [Abstract]
Net income as reported	$ 24,578	$ 26,648	$ 49,967	$ 38,136
Less: Distributed earnings available to participating securities		(10)		(18)
Less: Undistributed earnings available to participating securities				(14)
Numerator for basic earnings per share —
Undistributed and distributed earnings available to common shareholders	24,578	26,638	49,967	38,104
Add: Undistributed earnings allocated to participating securities				14
Less: Undistributed earnings reallocated to participating securities				(14)
Numerator for diluted earnings per share —
Undistributed and distributed earnings available to common shareholders	$ 24,578	$ 26,638	$ 49,967	$ 38,104
Denominator for basic earnings per share —
Weighted-average shares (in Shares)	22,579	22,296	22,536	22,197
Effect of dilutive securities:
Common stock equivalents (in Shares)	171	203	202	234
Denominator for diluted earnings per share —
Adjusted for weighted-average shares & assumed conversions (in Shares)	22,750	22,499	22,738	22,431
Basic earnings per share (in Dollars per share)	$ 1.09	$ 1.19	$ 2.21	$ 1.72
Diluted earnings per share (in Dollars per share)	$ 1.08	$ 1.18	$ 2.20	$ 1.70