Equity Method Investments Narrative (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 14,238	$ 12,925
Novasentis [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	27.90%
Equity method investments	$ 671	977
Nippon Yttrium Co., Ltd (NYC) [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	30.00%
Equity method investments	$ 7,884	8,215
NT Sales Co., Ltd (NTS) [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	33.00%
Equity method investments	$ 1,258	1,218
KEMET Jianghai [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	50.00%
Equity method investments	$ 4,425	$ 2,515
NT Sales Co., Ltd (NTS) [Member] | TOKIN [Member] | Discontinued Operations, Disposed of by Sale [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	67.00%