Note 19 - Enterprise-wide Disclosures - Revenue and Long-lived Assets (Details) - USD ($) $ in Thousands		3 Months Ended													12 Months Ended
		Dec. 30, 2018		Sep. 30, 2018	[2]	Jul. 01, 2018	[3]	Apr. 01, 2018	Dec. 31, 2017		Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	[5]	Dec. 30, 2018		Dec. 31, 2017		Jan. 01, 2017
Net Sales		$ 337,059	[1]	$ 318,325		$ 283,626		$ 240,563	$ 266,210	[4]	$ 257,431	$ 251,700	$ 221,102		$ 1,179,573	[6]	$ 996,443	[6]	$ 958,617	[6]
Long-lived assets	[7]	292,888							212,645						292,888		212,645
UNITED STATES
Net Sales	[6]														600,093		514,783		501,206
Long-lived assets	[7]	88,336							76,557						88,336		76,557
UNITED KINGDOM
Net Sales	[6]														65,406		57,391		58,266
Long-lived assets	[7]	6,288							7,902						6,288		7,902
AUSTRALIA
Net Sales	[6]														83,034		87,591		78,141
Long-lived assets	[7]	38,928							45,067						38,928		45,067
GERMANY
Net Sales	[6]														75,958		36,696		30,968
Long-lived assets	[7]	83,874							0						83,874		0
CHINA
Net Sales	[6]														43,708		28,279		31,340
Long-lived assets	[7]	6,703							8,361						6,703		8,361
Other Foreign Countries [Member]
Net Sales	[6]														311,374		271,703		258,696
Long-lived assets	[7]	3,700							3,083						3,700		3,083
NETHERLANDS
Long-lived assets	[7]	49,935							55,132						49,935		55,132
THAILAND
Long-lived assets		$ 15,124							$ 16,543						$ 15,124		$ 16,543

[1] Results for the fourth quarter of 2018 include tax benefit of $6.7 million as a result of the finalization of the Company's analysis of the U.S. Tax Cuts and Jobs Act, as well as restructuring and asset impairment charges of $20.5 million. Results for the fourth quarter of 2018 include purchase price accounting amortization of $11.8 million and transaction related expense of $1.2 million.

[2] Results for the third quarter of 2018 include purchase price accounting amortization of $20.3 million and transaction related expenses of $2.4 million.

[3] Results for the second quarter of 2018 include transaction related expenses of $5.8 million.

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

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

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

[7] Long-lived assets include tangible assets physically located in foreign countries.