Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2020	Jan. 31, 2019
Income Tax Contingency [Line Items]
Income tax expense (benefit)	$ (350)	$ 20	$ 1,822	$ 803
Effective income tax rate	15.50%	57.10%	104.50%	21.80%
Deferred tax liability, global tax exposure for unremitted earnings of international subsidiaries	$ 1,100		$ 1,100
Kewaunee Labway India \| Ministry of Finance, India
Income Tax Contingency [Line Items]
Effective income tax rate			20.60%
Dividend distribution tax withholding	$ 50		$ 2,214

Amount of deferred tax liability attributable to taxable temporary differences from undistributed earnings of subsidiaries and other recognized entities not within the country of domicile of the entity.

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