Nature of Operations and Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jan. 31, 2019	Jan. 31, 2019	Aug. 01, 2018
Nature Of Operations And Significant Accounting Policies [Line Items]
Cumulative effect of the change in accounting principle, net of tax	$ (5,450)	$ (5,450)
Accounting Standards Update 2014-09 | Retained Earnings
Nature Of Operations And Significant Accounting Policies [Line Items]
Cumulative effect of the change in accounting principle, net of tax			$ (5,450)
Accounting Standards Update 2014-09 | Accrued Promotions and Rebates
Nature Of Operations And Significant Accounting Policies [Line Items]
Cumulative effect of the change in accounting principle, net of tax			7,127
Cumulative effect of change on equity or net assets on pre-tax basis	$ 773	$ 1,506
Accounting Standards Update 2014-09 | Deferred Income Tax Assets
Nature Of Operations And Significant Accounting Policies [Line Items]
Cumulative effect of the change in accounting principle, net of tax			$ 1,677