Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands			12 Months Ended
	Oct. 01, 2020	Jan. 03, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Balance at beginning of period			$ 150,642	$ 147,480
Exchange rate effects			993	(162)
Balance at end of period			158,183	150,642	$ 147,480
Finite-Lived Intangible Assets [Line Items]
Intangible Assets Subject to Amortization			174,237	169,100
Accumulated amortization			(107,442)	(108,441)
Net Intangible Assets Subject to Amortization			66,795	60,659
Intangible assets, net			66,795	60,659
Amortization expense (excluding capitalized software)			8,113	8,476	11,807
Finite Lived Intangible Assets Future Amortization Expense [Abstract]
2021			7,920
2022			7,227
2023			6,992
2024			6,652
2025			6,384
Bi-Metallix [Member]
Goodwill [Roll Forward]
Goodwill acquired during period		$ 3,324		3,324
Applied Thin-Film Products [Member]
Goodwill [Roll Forward]
Goodwill acquired during period	$ 6,548		6,548
Optoelectronic Components [Member]
Goodwill [Roll Forward]
Balance at beginning of period			96,849	96,849
Exchange rate effects			0	0
Balance at end of period			96,849	96,849	96,849
Optoelectronic Components [Member] | Bi-Metallix [Member]
Goodwill [Roll Forward]
Goodwill acquired during period				0
Optoelectronic Components [Member] | Applied Thin-Film Products [Member]
Goodwill [Roll Forward]
Goodwill acquired during period			0
Resistors [Member]
Goodwill [Roll Forward]
Balance at beginning of period			27,978	24,816
Exchange rate effects			993	(162)
Balance at end of period			35,519	27,978	24,816
Resistors [Member] | Bi-Metallix [Member]
Goodwill [Roll Forward]
Goodwill acquired during period				3,324
Resistors [Member] | Applied Thin-Film Products [Member]
Goodwill [Roll Forward]
Goodwill acquired during period			6,548
Inductors [Member]
Goodwill [Roll Forward]
Balance at beginning of period			25,815	25,815
Exchange rate effects			0	0
Balance at end of period			25,815	25,815	$ 25,815
Inductors [Member] | Bi-Metallix [Member]
Goodwill [Roll Forward]
Goodwill acquired during period				0
Inductors [Member] | Applied Thin-Film Products [Member]
Goodwill [Roll Forward]
Goodwill acquired during period			0
Patents and Acquired Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets Subject to Amortization			21,259	31,125
Accumulated amortization			(14,340)	(24,905)
Capitalized Software [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets Subject to Amortization			58,419	55,862
Accumulated amortization			(52,990)	(50,976)
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets Subject to Amortization			71,454	59,603
Accumulated amortization			(28,659)	(23,871)
Tradenames [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets Subject to Amortization			23,105	22,510
Accumulated amortization			$ (11,453)	$ (8,689)