Note 13 - Selected Quarterly Financial Data (Unaudited) (Details Textual) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 30, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Dec. 31, 2016	Oct. 01, 2016	Jul. 02, 2016	Apr. 02, 2016	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability, Toll Charge	$ 49,000								$ 49,000
Business Combination, Acquisition Related Costs	1,400	$ 4,800	$ 300	$ 1,500	$ 3,200	$ 5,900	$ 6,100	$ 6,200
Legal Fees	$ 700	$ 1,500			1,200	900	100	400
Other Nonrecurring (Income) Expense					300	500	6,900
Asset Impairment Charges						$ 14,800
Facility Relocation [Member]
Restructuring Charges					$ 100		700	1,000
Facility Closing [Member]
Restructuring Charges							$ 300	$ 1,600