Financial Instruments - Financial Instruments and Balance Sheet Classification (Parenthetical) (Detail) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Apr. 30, 2019 |
Apr. 30, 2018 |
Apr. 30, 2017 |
|
| Investments Debt And Equity Securities [Abstract] | |||
| Obligations for which assets are held in trust | $ 122,300 | $ 118,200 | |
| Gain on marketable securities | 8,134 | 10,278 | $ 10,842 |
| Unvested obligations under deferred compensation plans | $ 24,600 | $ 29,500 | |
| X | ||||||||||
- Definition The amount of the liability included in the deferred compensation plans that is unvested and therefore the participants have not earned the right to. No definition available.
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount of unrealized and realized gain (loss) on investment in marketable security, excluding other-than-temporary impairment (OTTI). No definition available.
|
| X | ||||||||||
- Definition Amount of the liabilities for deferred compensation arrangements classified as other. No definition available.
|