Annual report pursuant to Section 13 and 15(d)

Supplemental Balance Sheets and Statements of Operations Detail Supplemental Balance Sheets and Statements of Operations - Inventory and Reserves (Details)

v3.19.1
Supplemental Balance Sheets and Statements of Operations Detail Supplemental Balance Sheets and Statements of Operations - Inventory and Reserves (Details) - USD ($)
$ in Thousands
12 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Mar. 31, 2017
Inventory [Line Items]      
Inventory, Raw Materials and Supplies, Gross $ 97,119 $ 88,408  
Inventory, Work in Process, Gross 71,374 65,417  
Inventory, Finished Goods, Gross 88,175 66,907  
Inventory, Gross 256,668 220,732  
Inventory Valuation Reserves 15,539 16,346  
Inventory, Net 241,129 204,386  
Inventory Valuation Reserve      
Inventory [Line Items]      
Balance at the beginning of the period 16,346 15,941 $ 16,101
Charged to Cost and Expense 6,019 4,994 6,163
Deductions 6,826 6,954 6,125
Other 0 2,365 (198)
Balance at the end of the period 15,539 $ 16,346 $ 15,941
Inventory Valuation Reserve | TOKIN      
Inventory [Line Items]      
Balance at the end of the period $ 1,900