| Cover Page - USD ($) | 12 Months Ended | ||
| Mar. 31, 2020 | May 26, 2020 | Sep. 30, 2018 | |
| Cover [Abstract] | |||
| Document Type | 10-K/A | ||
| Document Annual Report | true | ||
| Document Period End Date | Mar. 31, 2020 | ||
| Document Transition Report | false | ||
| Entity File Number | 001-15491 | ||
| Entity Registrant Name | KEMET Corp | ||
| Entity Incorporation, State or Country Code | DE | ||
| Entity Tax Identification Number | 57-0923789 | ||
| Entity Address, Address Line One | KEMET Tower, One East Broward Blvd. | ||
| Entity Address, City or Town | Fort Lauderdale | ||
| Entity Address, State or Province | FL | ||
| Entity Address, Postal Zip Code | 33301 | ||
| City Area Code | 954 | ||
| Local Phone Number | 766-2800 | ||
| Title of 12(b) Security | Common Stock, par value $0.01 | ||
| Trading Symbol | KEM | ||
| Security Exchange Name | NYSE | ||
| Entity Well-known Seasoned Issuer | Yes | ||
| Entity Voluntary Filers | No | ||
| Entity Current Reporting Status | Yes | ||
| Entity Interactive Data Current | Yes | ||
| Entity Filer Category | Large Accelerated Filer | ||
| Entity Small Business | false | ||
| Entity Emerging Growth Company | false | ||
| Entity Shell Company | false | ||
| Entity Public Float | $ 1,044,995,999 | ||
| Entity Common Stock, Shares Outstanding | 58,508,445 | ||
| Entity Central Index Key | 0000887730 | ||
| Amendment Flag | false | ||
| Current Fiscal Year End Date | --03-31 | ||
| Document Fiscal Year Focus | 2020 | ||
| Document Fiscal Period Focus | FY |
| Commitments and Contingencies - Narrative (Details) | 12 Months Ended |
| Mar. 31, 2020 | |
| Loss Contingencies [Line Items] | |
| Document Period End Date | Mar. 31, 2020 |
