Equity-Based Compensation - Black Scholes Options - Pricing Model (Details) - Stock Options - $ / shares	12 Months Ended
Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2018
Stock options
Volatility (as a percent)	49.86%	33.71%	30.86%
Expected life (years)	6 years	6 years	6 years
Risk-free interest rate (as a percent)	1.97%	2.87%	2.18%
Dividend yield (as a percent)	0.00%	0.00%	0.00%
Weighted average grant date fair value (in dollars per share)	$ 10.59	$ 9.72	$ 12.81

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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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.

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No definition available.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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