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		9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Computation of Basic and Diluted Earnings Per Share under the Two-class Method [Abstract]
Net income as reported	$ 29,940	$ 26,990	$ 79,907	$ 65,126
Less: Distributed earnings available to participating securities		(3)		(21)
Less: Undistributed earnings available to participating securities				(16)
Numerator for basic earnings per share —
Undistributed and distributed earnings available to common shareholders	29,940	26,987	79,907	65,089
Add: Undistributed earnings allocated to participating securities				16
Less: Undistributed earnings reallocated to participating securities				(16)
Numerator for diluted earnings per share —
Undistributed and distributed earnings available to common shareholders	$ 29,940	$ 26,987	$ 79,907	$ 65,089
Denominator for basic earnings per share —
Weighted-average shares (in Shares)	22,536	22,428	22,536	22,274
Effect of dilutive securities:
Common stock equivalents (in Shares)	153	197	186	223
Denominator for diluted earnings per share —
Adjusted for weighted-average shares & assumed conversions (in Shares)	22,689	22,625	22,722	22,497
Basic earnings per share (in Dollars per share)	$ 1.33	$ 1.20	$ 3.55	$ 2.92
Diluted earnings per share (in Dollars per share)	$ 1.32	$ 1.19	$ 3.52	$ 2.89