| Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Thousands | 12 Months Ended | ||
|---|---|---|---|
| Mar. 31, 2021 | Mar. 31, 2020 | Mar. 31, 2019 | |
| Statement Of Income And Comprehensive Income [Abstract] | |||
| Defined benefit pension and other postretirement plans, tax benefit | $ 509 | $ (153) | $ (63) | 
| X | ||||||||||
| 
- Definition Amount, after reclassification adjustment, of tax (expense) benefit for (increase) decrease in accumulated other comprehensive income of defined benefit plan. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
 | 
| X | ||||||||||
| 
- References No definition available. 
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