Annual report pursuant to Section 13 and 15(d)

Debt - Revolving Line of Credit, Narrative (Details)

v3.20.1
Debt - Revolving Line of Credit, Narrative (Details) - USD ($)
12 Months Ended
Mar. 31, 2020
May 02, 2016
Dec. 19, 2014
Sep. 30, 2010
Revolving line of credit        
Debt Instrument [Line Items]        
Credit facility, remaining borrowing capacity $ 34,300,000      
Revolving Line of Credit        
Debt Instrument [Line Items]        
Maximum borrowing capacity     $ 75,000,000.0 $ 50,000,000.0
Current borrowing capacity   $ 75,000,000.0 60,000,000.0  
Credit facility, remaining borrowing capacity     15,000,000.0  
Number of days considered 5 days      
Availability under credit facility (as a percent) 10.00%      
Availability under credit facility $ 7,500,000      
Fixed charge coverage ratio 1.0      
Consecutive period of non occurrence of any condition to maintain fixed charge coverage ratio 45 days      
Required aggregate revolver commitments to maintain fixed charge coverage ratio (as a percent) 10.00%      
Required aggregate revolver commitments to maintain fixed charge coverage ratio $ 7,500,000      
Revolving Line of Credit | LIBOR        
Debt Instrument [Line Items]        
Debt Instrument, Basis Spread on Variable Rate 1.00%      
Revolving Line of Credit | Greater than 33.3% and less than 66.6%        
Debt Instrument [Line Items]        
Unused line fee (as a percent) 0.50%      
Revolving Line of Credit | Greater than 33.3% and less than 66.6% | Maximum [Member]        
Debt Instrument [Line Items]        
Average daily balance as percentage of total revolving commitment 50.00%      
Revolving Line of Credit | Greater than or equal to 66.6%        
Debt Instrument [Line Items]        
Unused line fee (as a percent) 0.375%      
Revolving Line of Credit | Greater than or equal to 66.6% | Maximum [Member]        
Debt Instrument [Line Items]        
Average daily balance as percentage of total revolving commitment 50.00%      
Revolving Line of Credit | KEMET Singapore        
Debt Instrument [Line Items]        
Percentage of assets pledged as collateral 100.00%      
Foreign Line of Credit        
Debt Instrument [Line Items]        
Maximum borrowing capacity     $ 30,000,000.0  
Foreign Line of Credit | LIBOR | Minimum        
Debt Instrument [Line Items]        
Debt Instrument, Basis Spread on Variable Rate 2.25%      
Foreign Line of Credit | LIBOR | Maximum [Member]        
Debt Instrument [Line Items]        
Debt Instrument, Basis Spread on Variable Rate 2.75%      
Foreign Line of Credit | Base Rate | Minimum        
Debt Instrument [Line Items]        
Debt Instrument, Basis Spread on Variable Rate 1.25%      
Foreign Line of Credit | Base Rate | Maximum [Member]        
Debt Instrument [Line Items]        
Debt Instrument, Basis Spread on Variable Rate 1.75%      
Foreign Line of Credit | KEMET Singapore        
Debt Instrument [Line Items]        
Borrowing base component one, percentage of borrower's accounts receivable that satisfy certain eligibility criteria     85.00%  
Domestic Line of Credit        
Debt Instrument [Line Items]        
Number of days considered 5 days      
Availability under credit facility $ 3,800,000      
Required aggregate revolver commitments to maintain fixed charge coverage ratio $ 3,800,000      
Domestic Line of Credit | LIBOR | Minimum        
Debt Instrument [Line Items]        
Debt Instrument, Basis Spread on Variable Rate 2.00%      
Domestic Line of Credit | LIBOR | Maximum [Member]        
Debt Instrument [Line Items]        
Debt Instrument, Basis Spread on Variable Rate 2.50%      
Domestic Line of Credit | Base Rate | Minimum        
Debt Instrument [Line Items]        
Debt Instrument, Basis Spread on Variable Rate 1.00%      
Domestic Line of Credit | Base Rate | Maximum [Member]        
Debt Instrument [Line Items]        
Debt Instrument, Basis Spread on Variable Rate 1.50%      
Domestic Line of Credit | KEMET Electronics Corporation        
Debt Instrument [Line Items]        
Borrowing base component one, percentage of borrower's accounts receivable that satisfy certain eligibility criteria     85.00%  
Borrowing base component two, fixed amount for determining second component for borrowing base     $ 6,000,000.0  
Borrowing base component two, percentage of net book value of inventory of borrower that satisfies certain eligibility criteria     40.00%  
Borrowing base component three, percentage of net orderly liquidation percentage of the appraised value of inventory that satisfies certain eligibility criteria     85.00%  
Borrowing base component three, fixed amount for determining second component for borrowing base     $ 5,100,000  
Borrowing base component three, percentage of net orderly liquidation percentage of the appraised value of equipment that satisfies certain eligibility criteria     80.00%