Note 12 - Segment and Geographic Information - Business Unit Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jul. 02, 2016		Jun. 27, 2015	Jul. 02, 2016	Jun. 27, 2015
Electronics [Member]
Net sales		$ 132,170		$ 105,553	$ 230,966	$ 204,933
Depreciation and amortization		7,717		5,775	13,089	11,573
Operating income		25,259		22,167	47,675	40,832
Automotive [Member]
Net sales		111,370		85,918	203,303	169,989
Depreciation and amortization		4,988		3,303	8,254	6,639
Operating income		16,474		12,699	33,965	23,870
Industrial [Member]
Net sales		28,372		30,550	57,041	57,412
Depreciation and amortization		1,376		1,295	2,828	2,579
Operating income		2,028		4,709	3,701	7,439
Other Segments [Member]
Depreciation and amortization			[1]		937
Operating income	[2]	(14,059)		(3,404)	(23,211)	(6,422)
Net sales	[3]	271,912		222,021	491,310	432,334
Depreciation and amortization		14,081		10,373	25,108	20,791
Operating income		29,702		36,171	62,130	65,719
Interest expense		1,670		948	3,715	2,099
Foreign exchange (gain) loss		(6,237)		(1,292)	(2,414)	1,825
Other (income) expense, net		255		(1,202)	(262)	(2,328)
Income before income taxes		$ 34,014		$ 37,717	$ 61,091	$ 64,123

[1] Consists of intangible impairments. (See Note 13).

[2] Included in "Other" Operating income for the 2016 second quarter (and year-to-date) is $6.1 million ($12.3 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 $6.9 million ($6.9 million year-to-date) inventory adjustment relating to the PolySwitch acquisition as described in footnote 3, $0.3 million ($1.9 million year-to-date) in charges related to the closure of the company's manufacturing facility in Denmark, $0.7 million ($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 $0.1 million ($0.4 million year-to-date) related to internal legal restructuring costs.

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