Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

+ Details

Name:	us-gaap_AdjustmentForAmortization
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The percentage points added to the reference rate to compute the variable rate on the interest rate derivative.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeBasisSpreadOnVariableRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativesFairValueLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_CurrencyAxis=currency_MXN
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_FairValueHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=kem_CurrencySwapOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=kem_CurrencySwapTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CurrencyAxis=currency_JPY
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CurrencySwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CurrencyAxis=currency_USD
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_NetInvestmentHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Derivatives - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
Derivatives - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2018	Nov. 07, 2018	Mar. 31, 2018
Mexico, Pesos
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 72.2		$ 70.6
Fair Value Hedging \| Currency Swap One
Derivatives, Fair Value [Line Items]
Derivative, Basis Spread on Variable Rate	2.70%
Fair Value Hedging \| Currency Swap Two
Derivatives, Fair Value [Line Items]
Derivative, Basis Spread on Variable Rate	3.20%
Fair Value Hedging \| Japan, Yen \| Currency Swap One
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		$ 16,500.0
Amortization	$ 1,400.0
Derivative, Basis Spread on Variable Rate	2.00%
Fair Value Hedging \| Japan, Yen \| Currency Swap Two
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		16,500.0
Derivative, Basis Spread on Variable Rate	2.30%
Fair Value Hedging \| Japan, Yen \| Currency Swap
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 33,000.0
Fair Value Hedging \| United States of America, Dollars \| Currency Swap
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 291.9
Net Investment Hedging \| Currency Swap
Derivatives, Fair Value [Line Items]
Derivative, Basis Spread on Variable Rate	6.30%
Net Investment Hedging \| Japan, Yen \| Currency Swap Two
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		$ 33,000.0
Net Investment Hedging \| Japan, Yen \| Currency Swap
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 33,000.0
Amortization	$ 1,400.0
Derivative, Basis Spread on Variable Rate	2.60%
Net Investment Hedging \| United States of America, Dollars \| Currency Swap
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 291.9