Organization and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Apr. 30, 2018	May 01, 2018
Organization And Summary Of Significant Accounting Policies [Line Items]
Investments in affiliated companies maximum	50.00%
Impairment of goodwill	$ 0		$ 0
Impairment of intangible assets	0		$ 0
Purchase price allocated to indefinite lived trade name intangible assets	106,600,000
Performance related bonus expenses	61,000,000	$ 41,600,000
Accounting Standards Update 2014-09 | Adjustments Due to ASC 606
Organization And Summary Of Significant Accounting Policies [Line Items]
Increase to retained earnings, net of tax				$ 6,700,000
Accounting Standards Update 2018-02
Organization And Summary Of Significant Accounting Policies [Line Items]
Increase to retained earnings, net of tax	2,200,000
General and Administrative Expenses
Organization And Summary Of Significant Accounting Policies [Line Items]
Impairment of intangible assets	106,600,000
Compensation Expense | Accounting Standards Update 2017-07
Organization And Summary Of Significant Accounting Policies [Line Items]
Reclassification adjustment revised amount	1,200,000
Other Income | Accounting Standards Update 2017-07
Organization And Summary Of Significant Accounting Policies [Line Items]
Reclassification adjustment revised amount	(200,000)
Interest Expense | Accounting Standards Update 2017-07
Organization And Summary Of Significant Accounting Policies [Line Items]
Reclassification adjustment revised amount	$ (1,000,000)
Minimum
Organization And Summary Of Significant Accounting Policies [Line Items]
Intangible assets estimated useful lives	1 year
Amortization of long-term retention awards	4 years
Maximum
Organization And Summary Of Significant Accounting Policies [Line Items]
Intangible assets estimated useful lives	24 years
Amortization of long-term retention awards	5 years
Mexico Subsidiary
Organization And Summary Of Significant Accounting Policies [Line Items]
Percentage of Noncontrolling interest in subsidiary	51.00%