Accumulated Other Comprehensive Incom (Details) - USD ($) $ in Thousands |
Mar. 31, 2020 |
Mar. 31, 2019 |
Mar. 31, 2018 |
Mar. 31, 2017 |
|---|---|---|---|---|
| Equity [Abstract] | ||||
| Accumulated Other Comprehensive Income (Loss), Net of Tax | $ (235,463) | $ (159,778) | $ 11,685 | $ (240,702) |