Note 14 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended																12 Months Ended
		Dec. 31, 2016	[1]	Oct. 01, 2016	[2]	Jul. 02, 2016	[3]	Apr. 02, 2016	[4]	Jan. 02, 2016	[5]	Sep. 26, 2015	[6]	Jun. 27, 2015	[7]	Mar. 28, 2015	[8]	Dec. 31, 2016	Jan. 02, 2016	Dec. 27, 2014
Net sales		$ 284,518		$ 280,331		$ 271,912		$ 219,398		$ 220,020		$ 215,510		$ 222,021		$ 210,313		$ 1,056,159	$ 867,864	$ 851,995
Depreciation and amortization																		53,137	41,641	41,875
Operating income		$ 40,988		$ 27,526		$ 29,702		$ 32,428		$ 29,854		$ 8,584		$ 36,171		$ 29,548		130,644	104,157	133,830
Interest expense																		8,628	4,091	4,903
Foreign exchange loss (gain)																		472	(1,465)	3,925
Other expense (income), net																		(1,730)	(5,417)	(6,644)
Income before income taxes																		123,274	106,948	131,646
Electronics [Member]
Net sales																		535,191	405,497	410,065
Depreciation and amortization																		29,141	22,936	22,177
Operating income																		117,088	78,194	86,981
Automotive [Member]
Net sales																		415,200	339,957	325,415
Depreciation and amortization																		18,107	13,437	14,204
Operating income																		59,905	53,086	45,086
Industrial [Member]
Net sales																		105,768	122,410	116,515
Depreciation and amortization																		5,889	5,268	5,494
Operating income																		3,615	18,094	10,674
Other Segments [Member]
Operating income	[9]																	$ (49,964)	$ (45,217)	$ (8,911)

[1] In the fourth quarter of 2016, the company recorded ($0.1) million gain related to the company's transfer of its reed sensor manufacturing operations from the U.S. and China to the Philippines, $1.2 million of restructuring costs, $3.2 million in acquisition and integration costs and $0.3 million in non-cash inventory charges related to the 2016 acquisitions.

[2] In the third quarter of 2016, the company recorded $0.9 million of restructuring costs, $5.9 million in acquisition and integration costs, $14.8 million of charges related to the impairment of the custom products reporting unit and $0.5 million in non-cash inventory charges as noted above.

[3] In the second quarter of 2016, the company recorded $0.7 million related to the reed sensor manufacturing transfer as noted above, $0.1 million of restructuring costs, $6.1 million in acquisition and integration costs, $0.3 million in charges related to the closure of the manufacturing facility in Denmark and $6.9 million in non-cash inventory charges as noted above.

[4] In the first quarter of 2016, the company recorded $1.0 million related to the reed sensor manufacturing transfer as noted above, $0.4 million of restructuring costs, $6.2 million in acquisition and integration costs, and $1.6 million in charges related to the closure of the manufacturing facility in Denmark.

[5] In the fourth quarter of 2015, the company recorded $2.1 million related to the company's transfer of its reed switch manufacturing operations from the U.S. and China to the Philippines, ($0.1) million related to the reorganization of its internal legal structure, $4.0 million in acquisition costs, ($0.3) million in pension settlement refunds (See Note 10) and ($0.3) million in other.

[6] In the third quarter of 2015, the company recorded $1.2 million related to the reed switch manufacturing transfer as noted above, $0.9 million related to the company's reorganization of its internal legal structure as noted above, $0.3 million in acquisition costs, $30.8 million in pension settlement and wind-up costs (See Note 10) and $0.1 million in other.

[7] In the second quarter of 2015, the company recorded $0.9 million related to the reed switch manufacturing transfer as noted above, $1.7 million related to the company's reorganization of its internal legal structure as noted above, $0.2 million in acquisition costs, and $0.7 million in pension wind-up costs.

[8] In the first quarter of 2015, the company recorded $1.0 million related to the reed switch manufacturing transfer as noted above, $1.2 million in charges related to the reorganization of its internal legal structure as noted above, $0.2 million in acquisition costs, and $0.7 million in pension wind-up costs.

[9] Included in "Other" Operating income (loss) for 2016 are costs related to the impairment of the custom products reporting unit ($14.8 million), acquisition and integration costs associated with the company's 2016 acquisitions ($29.2 million in Cost of sales ("COS") and SG&A), transfer of the company's reed switch manufacturing operations from its Lake Mills, Wisconsin and Suzhou, China locations to the Philippines ($1.6 million in COS), impairment and severance costs related to the closure of the company's manufacturing facility in Denmark ($1.9 million in SG&A), and restructuring costs ($2.5 million in SG&A and R&D). Included in "Other" Operating income (loss) for 2015 are costs related to the transfer of the company's reed switch manufacturing operations from its Lake Mills, Wisconsin and Suzhou, China locations to the Philippines ($5.2 million in COS), acquisition related fees ($4.6 million included in SG&A), pension settlement and other costs ($31.9 million in SG&A), and restructuring costs ($3.6 million in SG&A). Included in "Other" Operating income (loss) for 2014 are acquisition related fees ($0.4 million included in SG&A), non-cash charges for the sale of inventory that had been stepped-up to fair value at the acquisition date of SymCom ($2.8 million included in COS), severance charges ($2.7 million in COS and $0.5 million in SG&A), restructuring costs ($2.2 million in SG&A) and asset impairments ($0.2 million in Research and development and $0.1 million in SG&A).