Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended	9 Months Ended
	Jan. 31, 2018	Apr. 30, 2018	Apr. 30, 2017
Income Tax Contingency [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		26.90%	35.00%
Federal Statutory Income Tax Rate, Percent		21.00%
Provisional Income Tax Expense Resulting from Changes in Tax Legislation (repatriation)	$ 402,000
Provisional Income Tax Expense Resulting from Changes in Tax Legislation (net of other disclosures)	18,832,000
Provisional Income Tax Expense Resulting from Changes in Tax Legislation (APB 23)	$ 1,826,000