Benefit Plans (Amounts recognized in balance sheets) (Details) - USD ($) $ in Thousands |
Mar. 31, 2020 |
Mar. 31, 2019 |
|---|---|---|
| Other Postretirement Benefit Plans, Defined Benefit | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Liability, Defined Benefit Plan, Current | $ (1,488) | $ (1,633) |
| Liability, Defined Benefit Plan, Noncurrent | (9,880) | (10,918) |
| Liability, Defined Benefit Pension Plan | (11,368) | (12,551) |
| Other Defined Benefit Pension Plans [Member] | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Liability, Defined Benefit Plan, Current | 0 | 0 |
| Liability, Defined Benefit Plan, Noncurrent | (10,987) | (16,168) |
| Liability, Defined Benefit Pension Plan | $ (10,987) | $ (16,168) |