Benefit Plans (Effect of one-percentage-point change in assumed healthcare cost trend rates) (Details) $ in Thousands |
12 Months Ended |
|---|---|
|
Mar. 31, 2020
USD ($)
| |
| Postemployment Benefits [Abstract] | |
| Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components | $ 0 |
| Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components | 0 |
| Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation | 7 |
| Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation | $ (6) |