Equity Method Investments - Reconciliation (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 16,593	$ 12,925
Nippon Yttrium Co., Ltd (NYC)
Schedule of Equity Method Investments [Line Items]
Equity method investments	8,617	8,215
NT Sales Co., Ltd (NTS)
Schedule of Equity Method Investments [Line Items]
Equity method investments	1,509	1,218
KEMET Jianghai Electronics Components Co., Ltd (“KEMET Jianghai”)
Schedule of Equity Method Investments [Line Items]
Equity method investments	6,467	2,515
Novasentis
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 0	$ 977