Note 10 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
Net sales		$ 317,889	$ 280,331	$ 916,685	$ 771,641
Depreciation and amortization		15,946	13,117	46,634	38,225
Operating income		58,609	27,526	167,731	89,656
Interest expense		3,467	2,571	9,868	6,286
Foreign exchange loss (gain)		632	(4,700)	(1,483)	(7,114)
Other income, net		(1,013)	(778)	(962)	(1,040)
Income before income taxes		55,523	30,433	160,308	91,524
Electronics [Member]
Net sales		175,899	147,730	499,052	378,696
Depreciation and amortization		8,986	7,694	26,080	20,783
Operating income		44,345	34,571	122,518	82,246
Automotive [Member]
Net sales		113,797	106,341	338,094	309,644
Depreciation and amortization		5,622	4,627	16,572	12,881
Operating income		16,821	15,032	47,599	48,997
Industrial [Member]
Net sales		28,193	26,260	79,539	83,301
Depreciation and amortization		1,338	1,733	3,982	4,561
Operating income		3,757	57	5,769	3,758
Other Segments [Member]
Depreciation and amortization			(937)
Operating income	[1]	$ (6,314)	$ (22,134)	$ (8,155)	$ (45,345)

[1] Included in "Other" Operating income (loss) for the 2017 third quarter is $4.8 million ($6.6 million year-to-date) of acquisition-related and integration charges associated with the company's acquisitions, $1.6 million ($1.6 million year-to-date) of purchase accounting inventory charges related to the company's 2017 acquisition of US Sensor as described in Note 2 and $1.5 million ($1.5 million year-to-date) of charges related to restructuring and production transfers in our Asia operations. Included in "Other' Operating income (loss) for the 2016 third quarter is $14.8 million (14.8 million year-to-date) of charges related to the impairment of goodwill and other intangible assets within the custom products reporting unit, $5.9 million ($18.2 million year-to-date) of acquisition-related and integration charges associated with the company's 2016 acquisitions, $0.6 million ($7.5 million year-to-date) of non-cash inventory charges relating to the company’s 2016 acquisitions as described in Note 2, $1.9 million year-to-date in charges related to the closure of the company's manufacturing facility in Denmark, $1.7 million year-to-date related to the company's transfer of its reed sensor manufacturing operations from the U.S. and China to the Philippines and $0.9 million ($1.3 million year-to-date) related to internal legal restructuring costs.