Investment in NEC TOKIN Investment in NEC TOKIN (Details 3) (Details) (USD $)	6 Months Ended	12 Months Ended
	Sep. 30, 2014	Mar. 31, 2014
Schedule of Equity Method Investments [Line Items]
Investment in NEC TOKIN	$ 48,449,000	$ 46,419,000
Nectokin Corporation
Schedule of Equity Method Investments [Line Items]
Investment in NEC TOKIN	48,449,000	46,419,000
Property, plant and equipment	7,116,000	7,325,000
Technology	(15,450,000)	(16,261,000)
Long-term debt	(4,254,000)	(4,754,000)
Goodwill	(9,326,000)	(9,326,000)
Other	(834,000)	(952,000)
KEMET's 34% economic interest of NEC TOKIN's net assets	25,701,000	22,451,000
Sales to NEC TOKIN	4,000,000	5,900,000
Accounts receivable	1,800,000	2,000,000
Accounts payable	100,000	100,000
Stockholders' Agreement | KEC
Schedule of Equity Method Investments [Line Items]
Receivable balances	$ 500,000	$ 700,000