Annual report pursuant to Section 13 and 15(d)

Equity Method Investments - Investment in TOKIN (Details)

v3.19.1
Equity Method Investments - Investment in TOKIN (Details)
$ in Thousands, ¥ in Billions
12 Months Ended
Apr. 19, 2017
USD ($)
Apr. 19, 2017
JPY (¥)
Mar. 31, 2019
USD ($)
Mar. 31, 2018
USD ($)
Mar. 31, 2017
USD ($)
Dec. 31, 2017
USD ($)
May 05, 2010
Schedule of Equity Method Investments [Line Items]              
Change in value of TOKIN options     $ 0 $ 0 $ 10,700    
TOKIN              
Schedule of Equity Method Investments [Line Items]              
Transaction expenses           $ 900  
10.5% Senior Notes              
Schedule of Equity Method Investments [Line Items]              
Stated interest rate (as a percent)             10.50%
KEC | TOKIN              
Schedule of Equity Method Investments [Line Items]              
Ownership percentage 100.00% 100.00%          
Purchase price paid $ 148,600 ¥ 16.2          
Interest acquired 66.00% 66.00%          
NEC TOKIN Corporation | Stock Purchase Agreement | KEMET Electronics Corporation              
Schedule of Equity Method Investments [Line Items]              
Ownership percentage 34.00% 34.00%   34.00% 34.00% 34.00%  
NEC TOKIN Corporation | Put Option | Recurring | Level 3              
Schedule of Equity Method Investments [Line Items]              
Change in value of TOKIN options       $ 10,700