Income Taxes - Changes in Carrying Amount of Valuation Allowance (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Apr. 30, 2026 |
Apr. 30, 2025 |
Apr. 30, 2024 |
|
| Deferred Tax Assets, Valuation Allowance [Roll Forward] | |||
| Balance at beginning of year | $ 18.0 | $ 13.0 | $ 27.0 |
| Increase (decrease) in valuation allowance | 6.0 | 4.0 | (14.0) |
| Foreign exchange | 0.0 | 1.0 | 0.0 |
| Balance at end of year | $ 24.0 | $ 18.0 | $ 13.0 |