Basis of Financial Statement Presentation - Revenue Recognition Narrative (Details)	3 Months Ended
Jun. 30, 2018	Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Maximum percentage of purchased inventory that can be returned by distributor	6.00%
Period of product warranty	1 year
Warranty costs as a percentage of net sales, maximum	1.00%	1.00%

Represents the maximum expense as a percentage of net sales, charged against earnings during the period pertaining to standard and extended warranties on the entity's goods and services granted to customers.

No definition available.

Name:	kem_ProductWarrantyExpenseAsPercentageOfNetSalesMaximum
Namespace Prefix:	kem_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration