Employee Benefit Plans (Defined Contribution Plans Narrative) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
---|---|---|---|
Mar. 31, 2019 |
Mar. 31, 2018 |
Mar. 31, 2017 |
|
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |||
Expense for defined contribution plans | $ 8.7 | $ 7.6 | $ 5.8 |