Organization and Significant Accounting Policies - Revenue Recognition (Details)	12 Months Ended
Mar. 31, 2018
Accounting Policies [Abstract]
Maximum percentage of purchased inventory that can be returned by distributor	6.00%
Product warranty period	1 year
Product warranty expense as percentage of net sales maximum	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