Goodwill and Intangible Assets Schedule of Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Goodwill [Line Items]
Goodwill	$ 41,210	$ 40,294	$ 40,294
Goodwill, Acquired During Period	916	0
Solid Capacitors
Goodwill [Line Items]
Goodwill	35,584	35,584	35,584
Goodwill, Acquired During Period	0	0
Film and Electrolytic
Goodwill [Line Items]
Goodwill	916	0	0
Goodwill, Acquired During Period	916	0
Electro-magnetic, Sensors & Actuators [Member]
Goodwill [Line Items]
Goodwill	0	0	0
Goodwill, Acquired During Period	0	0
Corporate
Goodwill [Line Items]
Goodwill	4,710	4,710	$ 4,710
Goodwill, Acquired During Period	0	$ 0
Novasentis \| Film and Electrolytic
Goodwill [Line Items]
Goodwill	$ 900

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 350
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-Section 45
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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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