Note 16 - Enterprise-wide Disclosures - Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended											12 Months Ended
	Dec. 31, 2017		Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	[2]	Jan. 01, 2017		Oct. 02, 2016	Jul. 03, 2016	Apr. 03, 2016	Dec. 31, 2017		Jan. 01, 2017		Jan. 03, 2016
Net sales	$ 266,210	[1]	$ 257,431	$ 251,700	$ 221,102		$ 239,507	[3]	$ 248,349	$ 248,207	$ 222,554	$ 996,443	[4]	$ 958,617	[4]	$ 1,001,863	[4]
Depreciation and amortization												30,261		30,632		30,803
Total assets	800,600						835,439					800,600		835,439
Operating Segments [Member]
Net sales												996,443		958,617		1,001,863
Depreciation and amortization												28,259		29,066		29,564
Total assets	719,957						737,399					719,957		737,399
Americas [Member] | Operating Segments [Member]
Net sales												588,052		568,138		593,163
Depreciation and amortization												13,548		14,639		15,390
Total assets	272,883						237,900					272,883		237,900
Europe [Member] | Operating Segments [Member]
Net sales												246,399		241,463		262,671
Depreciation and amortization												6,049		5,698		5,007
Total assets	253,519						261,182					253,519		261,182
Asia Pacific [Member] | Operating Segments [Member]
Net sales												161,992		149,016		146,029
Depreciation and amortization												8,662		8,729		$ 9,167
Total assets	$ 193,555						$ 238,317					$ 193,555		$ 238,317

[1] Results for the fourth quarter of 2017 include tax charges of $15.2 million as a result of the recently enacted U.S. Tax Cuts and Jobs Act.

[2] Results for the first quarter of 2017 include restructuring and asset impairment charges of $7.3 million.

[3] Results for the fourth quarter of 2016 include restructuring and asset impairment charges of $19.8 million.

[4] Revenue attributed to geographic areas is based on the location of the customer.