Note 13 - Taxes on Income - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Jan. 03, 2016
Income taxes at U.S. federal statutory rate	$ 35,189	$ 27,698	$ 37,018
State income taxes, net of federal tax effect	2,677	1,861	3,003
Non-deductible business expenses	695	538	614
Non-deductible employee compensation	80	361	168
Tax effects of Company owned life insurance	(1,295)	(199)	128
One-time transition tax on foreign earnings	11,707	0	0
Remeasurement of net Deferred Tax Asset	3,467	0	0
Tax effects of undistributed earnings from foreign subsidiaries not deemed to be indefinitely reinvested	523	463	458
Foreign and U.S. tax effects attributable to foreign operations	(4,537)	(3,963)	(3,347)
Valuation allowance effect – State NOL	(858)	(1,272)	(3,797)
Federal tax credits	(442)	(494)	(352)
Other	87	(19)	(545)
Total income tax expense	$ 47,293	$ 24,974	$ 33,348