Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Income Tax Contingency [Line Items]
Income tax expense	$ 2,003	$ 388	$ 2,172	$ 783
Effective income tax rate	1267.70%	22.00%	428.40%	21.40%
Deferred tax liability, global tax exposure for unremitted earnings of international subsidiaries	$ 1,730		$ 1,730
Kewaunee Labway India \| Ministry of Finance, India
Income Tax Contingency [Line Items]
Effective income tax rate			20.60%
Dividend distribution tax withholding			$ 353

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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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