Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Balance at beginning of period	$ 141,407	$ 138,244
Goodwill impairment loss	0	0	$ (5,380)
Exchange rate effects	1,335	(322)
Balance at end of period	142,742	141,407	138,244
Finite-Lived Intangible Assets [Line Items]
Intangible Assets Subject to Amortization	245,454	287,053
Accumulated amortization	(175,700)	(202,590)
Net Intangible Assets Subject to Amortization	69,754	84,463
Intangible assets, net	69,754	84,463
Amortization expense (excluding capitalized software)	14,263	14,842	21,829
Finite Lived Intangible Assets Future Amortization Expense [Abstract]
2018	11,620
2019	7,741
2020	6,750
2021	5,863
2022	5,192
Sonntag [Member]
Goodwill [Roll Forward]
Goodwill acquired during period		3,485
Capella Microsystems (Taiwan) Inc. [Member]
Goodwill [Roll Forward]
Impairment of Long-Lived Assets Held-for-use			57,600
Resistors And Inductors Segment [Member]
Goodwill [Roll Forward]
Balance at beginning of period	44,558	41,395
Exchange rate effects	1,335	(322)
Balance at end of period	45,893	44,558	41,395
Resistors And Inductors Segment [Member] | Sonntag [Member]
Goodwill [Roll Forward]
Goodwill acquired during period		3,485
Optoelectronic Components Segment [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 Segment [Member] | Sonntag [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	71,596	93,395
Accumulated amortization	(63,868)	(81,807)
Capitalized Software [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets Subject to Amortization	54,325	53,807
Accumulated amortization	(50,246)	(49,388)
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets Subject to Amortization	63,655	84,905
Accumulated amortization	(26,622)	(42,787)
Tradenames [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets Subject to Amortization	55,272	53,680
Accumulated amortization	(34,378)	(27,460)
Non-competition Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets Subject to Amortization	606	1,266
Accumulated amortization	$ (586)	$ (1,148)