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)

v3.20.1
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, 2020
Mar. 31, 2019
Mar. 31, 2018
Inventory [Line Items]      
Raw materials and supplies $ 93,464 $ 97,119  
Work in process 85,122 71,374  
Finished goods 82,311 88,175  
Inventory gross 260,897 256,668  
Inventory reserves (17,687) (15,539)  
Inventory, net 243,210 241,129  
Inventory Valuation Reserve      
Inventory [Line Items]      
Balance at the beginning of the period 15,539 16,346 $ 15,941
Charge (benefit) to costs and expenses 12,623 6,019 4,994
Deductions (10,867) (6,826) (6,954)
Other 392 0 2,365
Balance at the end of the period 17,687 $ 15,539 $ 16,346
Inventory Valuation Reserve | TOKIN      
Inventory [Line Items]      
Balance at the end of the period $ 1,900