Note 2 - Correction of Immaterial Errors - Effects of Adjustments to Correct Immaterial Errors, Statements of Net Income (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended			12 Months Ended
	Oct. 01, 2016	Sep. 26, 2015	Oct. 01, 2016	Oct. 01, 2016	Sep. 26, 2015	Jan. 02, 2016	Dec. 27, 2014
Scenario, Previously Reported [Member]
Income Tax Expense (Benefit)						$ 24,482	$ 32,228
Net income						$ 82,466	$ 99,418
Net income per share - Basic (in dollars per share)						$ 3.65	$ 4.41
Net income per share - 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)
Net income per share - Basic (in dollars per share)						$ (0.07)	$ (0.06)
Net income per share - Diluted (in dollars per share)						$ (0.07)	$ (0.05)
Income Tax Expense (Benefit)	$ (369)	$ 1,317		$ 14,281	$ 16,761	$ 26,082	$ 33,546
Net income	$ 30,802	$ 11,324	$ 77,243	$ 77,243	$ 60,003	$ 80,866	$ 98,100
Net income per share - Basic (in dollars per share)	$ 1.36	$ 0.50		$ 3.43	$ 2.65	$ 3.58	$ 4.35
Net income per share - Diluted (in dollars per share)	$ 1.35	$ 0.50		$ 3.41	$ 2.64	$ 3.56	$ 4.32