Annual report pursuant to Section 13 and 15(d)

Acquisitions Acquisitions - Components of the Acquisition Price (Details)

v3.19.1
Acquisitions Acquisitions - Components of the Acquisition Price (Details)
$ in Thousands, ¥ in Billions
Apr. 19, 2017
USD ($)
Rate
Apr. 19, 2017
JPY (¥)
Mar. 31, 2018
Rate
Dec. 31, 2017
USD ($)
Rate
Dec. 31, 2017
JPY (¥)
Rate
Sep. 30, 2017
Rate
Apr. 19, 2017
JPY (¥)
Rate
Apr. 14, 2017
USD ($)
Apr. 14, 2017
JPY (¥)
Business Acquisition [Line Items]                  
Exchange rate | Rate 10900.70%   11182.30% 11257.40% 11257.40% 11250.20% 10900.70%    
Indemnity asset for legal investigation $ 8,500                
Equity Method Investments | Stockholders Agreement                  
Business Acquisition [Line Items]                  
Indemnification assets, low range of outcomes       $ 25,000          
TOKIN                  
Business Acquisition [Line Items]                  
Net consideration transferred 150,358                
Purchase price       $ 10,100 ¥ 1.1   ¥ 10.2 $ 431,000 ¥ 48.2
TOKIN | KEC                  
Business Acquisition [Line Items]                  
Upfront cash consideration $ 148,600 ¥ 16.2              
Interest acquired 66.00%           66.00%    
TOKIN | KEC | Cash Distribution                  
Business Acquisition [Line Items]                  
Upfront cash consideration $ 55,000 6.0              
TOKIN | KEC | Excess cash                  
Business Acquisition [Line Items]                  
Upfront cash consideration 93,600 ¥ 10.2              
Cash Distribution | TOKIN                  
Business Acquisition [Line Items]                  
Upfront cash consideration 148,614                
Acquisition-related Costs | TOKIN                  
Business Acquisition [Line Items]                  
Acquisition payable 3,144                
Other Assets | TOKIN                  
Business Acquisition [Line Items]                  
Indemnity asset 8,500                
Put Option | TOKIN                  
Business Acquisition [Line Items]                  
Less: Put option (9,900)                
Net derivative asset (liability) $ (9,900)