Comprehensive Income - Changes in Each Component of Accumulated Other Comprehensive Income (Loss) (Parenthetical) (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
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Apr. 30, 2020 |
Apr. 30, 2019 |
Apr. 30, 2018 |
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| Deferred Compensation and Pension Plan | |||
| Accumulated Other Comprehensive Income (Loss) [Line Items] | |||
| Tax effect on unrealized (losses) gains | $ (3.1) | $ (2.3) | $ 2.5 |
| Tax effect on reclassification of realized net losses (gains) | 0.8 | 0.4 | 0.8 |
| Unrealized (Losses) Gains on Interest Rate Swap | |||
| Accumulated Other Comprehensive Income (Loss) [Line Items] | |||
| Tax effect on unrealized (losses) gains | (0.2) | (0.3) | 0.8 |
| Tax effect on reclassifications of realized net gains (losses) | $ (0.1) | $ 0.1 | $ (0.3) |
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Amount, before reclassification adjustment, of tax (expense) benefit for (increase) decrease in accumulated other comprehensive income for defined benefit plan. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of tax (expense) benefit for reclassification adjustment from accumulated other comprehensive (income) loss of defined benefit plan. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of tax expense (benefit), before reclassification adjustments, related to increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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