Income Taxes (Details) - USD ($) $ in Millions	9 Months Ended
Jan. 31, 2020	Jan. 31, 2019	Apr. 30, 2019
Effective income tax rate (as a percent)	22.00%	23.90%
Reserve for uncertain tax positions	$ 0.0		$ 0.0
Valuation allowance	$ 1.4		$ 1.1
Domestic
Federal statutory rate (as a percent)	21.00%

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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