Organization and Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		6 Months Ended		12 Months Ended
	Oct. 31, 2019 USD ($)	Oct. 31, 2018 USD ($)	Oct. 31, 2019 USD ($) Segment	Oct. 31, 2018 USD ($)	Apr. 30, 2019 USD ($)
Organization And Summary Of Significant Accounting Policies [Line Items]
Number of business segments | Segment			3
Impairment of goodwill			$ 0		$ 0
Impairment of intangible assets			0		$ 0
Purchase price allocated to indefinite lived trade name intangible assets		$ 106,600,000		$ 106,600,000
Performance-related bonus expenses	$ 64,400,000	$ 81,900,000	117,400,000	142,900,000
Accounting Standards Update 2016-02
Organization And Summary Of Significant Accounting Policies [Line Items]
ROU assets	236,100,000		236,100,000
Lease liability	$ 272,300,000		272,300,000
ROU asset adjusted by reclassification of pre-existing prepaid expenses and other assets			5,100,000
ROU asset adjusted by reclassification of deferred rent			$ 41,300,000
General and Administrative Expenses
Organization And Summary Of Significant Accounting Policies [Line Items]
Impairment of intangible assets				$ 106,600,000
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
Affiliated Entity
Organization And Summary Of Significant Accounting Policies [Line Items]
Investments in affiliated companies maximum	50.00%		50.00%
Mexico Subsidiary
Organization And Summary Of Significant Accounting Policies [Line Items]
Percentage of Noncontrolling interest in subsidiary	51.00%		51.00%