Note 2 - Correction of Immaterial Errors - Effects of Adjustments to Correct Immaterial Errors, Statements of Net Income (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Jan. 02, 2016	Dec. 27, 2014
Income Tax Expense (Benefit)	$ 18,786	$ 26,082	$ 33,546
Net income	$ 104,488	$ 80,866	$ 98,100
Basic (in dollars per share)	$ 4.63	$ 3.58	$ 4.35
Diluted (in dollars per share)	$ 4.60	$ 3.56	$ 4.32
Scenario, Previously Reported [Member]
Income Tax Expense (Benefit)		$ 24,482	$ 32,228
Net income		$ 82,466	$ 99,418
Basic (in dollars per share)		$ 3.65	$ 4.41
Diluted (in dollars per share)		$ 3.63	$ 4.37
Restatement Adjustment [Member]
Income Tax Expense (Benefit)		$ 1,600	$ 1,318
Net income		$ (1,600)	$ (1,318)
Basic (in dollars per share)		$ (0.07)	$ (0.06)
Diluted (in dollars per share)		$ (0.07)	$ (0.05)