Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands				12 Months Ended
	Jan. 03, 2019	Jun. 11, 2018	Feb. 08, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Balance at beginning of period				$ 147,480	$ 142,742
Exchange rate effects				(162)	(557)
Balance at end of period				150,642	147,480	$ 142,742
Finite-Lived Intangible Assets [Line Items]
Intangible Assets Subject to Amortization				169,100	168,232
Accumulated amortization				(108,441)	(102,544)
Net Intangible Assets Subject to Amortization				60,659	65,688
Intangible assets, net				60,659	65,688
Amortization expense (excluding capitalized software)				8,476	11,807	14,263
Finite Lived Intangible Assets Future Amortization Expense [Abstract]
2020				7,886
2021				6,688
2022				6,044
2023				5,824
2024				5,507
UltraSource [Member]
Goodwill [Roll Forward]
Goodwill acquired during period			$ 4,227		4,227
EuroPower [Member]
Goodwill [Roll Forward]
Goodwill acquired during period		$ 1,068			1,068
Bi-Metallix [Member]
Goodwill [Roll Forward]
Goodwill acquired during period	$ 3,324			3,324
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] | UltraSource [Member]
Goodwill [Roll Forward]
Goodwill acquired during period					0
Optoelectronic Components [Member] | EuroPower [Member]
Goodwill [Roll Forward]
Goodwill acquired during period					0
Optoelectronic Components [Member] | Bi-Metallix [Member]
Goodwill [Roll Forward]
Goodwill acquired during period				0
Resistors [Member]
Goodwill [Roll Forward]
Balance at beginning of period				24,816	20,078
Exchange rate effects				(162)	(557)
Balance at end of period				27,978	24,816	20,078
Resistors [Member] | UltraSource [Member]
Goodwill [Roll Forward]
Goodwill acquired during period					4,227
Resistors [Member] | EuroPower [Member]
Goodwill [Roll Forward]
Goodwill acquired during period					1,068
Resistors [Member] | Bi-Metallix [Member]
Goodwill [Roll Forward]
Goodwill acquired during period				3,324
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] | UltraSource [Member]
Goodwill [Roll Forward]
Goodwill acquired during period					0
Inductors [Member] | EuroPower [Member]
Goodwill [Roll Forward]
Goodwill acquired during period					0
Inductors [Member] | Bi-Metallix [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				31,125	32,854
Accumulated amortization				(24,905)	(26,469)
Capitalized Software [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets Subject to Amortization				55,862	53,218
Accumulated amortization				(50,976)	(49,288)
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets Subject to Amortization				59,603	59,119
Accumulated amortization				(23,871)	(19,958)
Tradenames [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets Subject to Amortization				22,510	23,041
Accumulated amortization				$ (8,689)	$ (6,829)