Annual report pursuant to Section 13 and 15(d)

Acquisitions - Narrative (Details)

v3.19.1
Acquisitions - Narrative (Details)
$ in Thousands, ¥ in Billions
3 Months Ended 12 Months Ended
Apr. 19, 2017
USD ($)
Apr. 19, 2017
JPY (¥)
Rate
Mar. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Sep. 30, 2018
USD ($)
Jun. 30, 2018
USD ($)
Mar. 31, 2018
USD ($)
Rate
Dec. 31, 2017
USD ($)
manufacturing_site
Rate
Sep. 30, 2017
USD ($)
Rate
Jun. 30, 2017
USD ($)
Mar. 31, 2019
USD ($)
Mar. 31, 2018
USD ($)
Rate
Mar. 31, 2017
USD ($)
Dec. 31, 2017
JPY (¥)
manufacturing_site
Rate
Apr. 14, 2017
USD ($)
Apr. 14, 2017
JPY (¥)
Acquisitions                                
Exchange rate | Rate   10900.70%         11182.30% 11257.40% 11250.20%     11182.30%   11257.40%    
Working capital adjustment               $ 0           ¥ 0.3    
Revenue from Contract with Customer, Excluding Assessed Tax                     $ 1,382,818 $ 1,200,181 $ 757,338      
Operating income (loss)     $ 54,057 $ 61,616 $ 50,000 $ 35,176 $ 21,646 32,002 $ 31,597 $ 27,607 200,849 112,852 $ 34,968      
TOKIN                                
Acquisitions                                
Transaction expenses               $ 900                
Revenue from Contract with Customer, Excluding Assessed Tax                     370,200 358,200        
Operating income (loss)                     $ 34,800 $ 36,100        
TOKIN                                
Acquisitions                                
Number of manufacturing sites | manufacturing_site               6           6    
Purchase price   ¥ 10.2           $ 10,100           ¥ 1.1 $ 431,000 ¥ 48.2
KEC | TOKIN                                
Acquisitions                                
Ownership percentage   100.00%                            
Interest acquired   66.00%                            
Purchase price paid $ 148,600 ¥ 16.2                            
KEC | Cash Distribution | TOKIN                                
Acquisitions                                
Purchase price paid 55,000 6.0                            
KEC | Excess cash | TOKIN                                
Acquisitions                                
Purchase price paid 93,600 ¥ 10.2                            
NEC TOKIN Corporation | KEMET Electronics Corporation | Stock Purchase Agreement                                
Acquisitions                                
Ownership percentage   34.00%         34.00% 34.00%       34.00% 34.00% 34.00%    
Equity interest in acquiree $ 204,112