Note 13 - Segment and Geographic Information - Business Unit Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Oct. 01, 2016		Sep. 26, 2015	Oct. 01, 2016	Sep. 26, 2015
Electronics [Member]
Net sales		$ 147,730		$ 102,616	$ 378,696	$ 307,549
Depreciation and amortization		7,694		5,811	20,783	17,384
Operating income		34,571		20,923	82,246	61,755
Automotive [Member]
Net sales		106,341		81,475	309,644	251,464
Depreciation and amortization		4,627		3,244	12,881	9,883
Operating income		15,032		15,253	48,997	39,123
Industrial [Member]
Net sales		26,260		31,419	83,301	88,831
Depreciation and amortization		1,733		1,260	4,561	3,839
Operating income		57		5,781	3,758	13,220
Other Segments [Member]
Depreciation and amortization		(937)	[1]
Operating income	[2]	(22,134)		(33,373)	(45,345)	(39,795)
Net sales	[3]	280,331		215,510	771,641	647,844
Depreciation and amortization		13,117		10,315	38,225	31,106
Operating income		27,526		8,584	89,656	74,303
Interest expense		2,571		922	6,286	3,021
Foreign exchange (gain) loss		(4,700)		(3,549)	(7,114)	(1,724)
Other (income) expense, net		(778)		(1,430)	(1,040)	(3,758)
Income before income taxes		$ 30,433		$ 12,641	$ 91,524	$ 76,764

[1] Consists of intangible impairments related to its loss on sale of product line. (See Note 15).

[2] 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 the custom business unit, $5.9 million ($18.2 million year-to-date) of acquisition-related costs primarily related to legal and integration costs associated with the company's acquisition of the PolySwitch business, a $0.6 million ($7.5 million year-to-date) inventory adjustment relating to the PolySwitch acquisition as described in Note 4, $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.

[3] Sales by country represent sales to customer or distributor locations.