Note 4 - Earnings Per Share - Calculation of Income (Loss) Per Shares (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
Apr. 01, 2018	Apr. 02, 2017
Net income	$ 15,084	$ 8,547
Shares for Basic Earnings Per Share (in shares)	59,671	64,081
Dilutive Effect of Stock Options (in shares)	46	42
Shares for Diluted Earnings Per Share (in shares)	59,717	64,123
Participating Securities [Member]
Net income	$ 200	$ 100
Weighted Average Shares Outstanding (in shares)	59,069	63,635
Participating Securities (in shares)	602	446

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