Investment in NEC TOKIN NEC Tokin Equity Method Investment (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Mar. 31, 2015 USD ($)
Schedule of Equity Method Investments [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	$ 2,200	$ 6,600	$ (27,000)	$ 10,700
Investment in NEC TOKIN	42,156		$ 42,156		$ 45,016
Loss Contingency, Number of Co-Defendants			20
Loss Contingency, Estimate of Possible Loss	30,000		$ 30,000
Nectokin Corporation [Member]
Schedule of Equity Method Investments [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	2,200		27,000
Investment in NEC TOKIN	42,156		42,156		45,016
Property, plant and equipment	3,284		3,284		3,334
Technology	(10,162)		(10,162)		(10,889)
Long-term debt	(2,272)		(2,272)		(2,707)
Goodwill	(7,060)		(7,060)		(7,082)
Legal Fees	(8,500)		(8,500)		(8,500)
Equity Method Investment, Unrecognized Profit Elimination	306		306		208
Other	(581)		(581)		(39)
KEC's 34% economic interest in NEC TOKIN's net assets	17,171		17,171		19,341
Accounts receivable	3,136		3,136		3,344
Accounts payable	726		726		765
Sales to NEC TOKIN	4,474	3,957	9,330	5,888
Related Party Transaction, Purchases from Related Party	$ 2,112	$ 618	$ 3,590	$ 1,118
KEC's economic interest %	34.00%	34.00%	34.00%	34.00%
KEMET Electronics Corporation [Member]
Schedule of Equity Method Investments [Line Items]
Business Combination, Indemnification Assets, Range of Outcomes, Value, Low	$ 8,500		$ 8,500
Stockholders Agreement [Member] | KEMET Electronics Corporation [Member]
Schedule of Equity Method Investments [Line Items]
Receivable balances	504		504		$ 572
Equity Method Investments [Member] | Stockholders Agreement [Member]
Schedule of Equity Method Investments [Line Items]
Business Combination, Indemnification Assets, Range of Outcomes, Value, Low	$ 25,000		$ 25,000
Indemnification Agreement [Member] | Equity Method Investments [Member]
Schedule of Equity Method Investments [Line Items]
Business Combination, Indemnification Assets, Basis for Amount	13800000
Settled Litigation [Member] | Indemnification Agreement [Member] | Equity Method Investments [Member]
Schedule of Equity Method Investments [Line Items]
Business Combination, Indemnification Assets, Basis for Amount	2300000