Organization and Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 31, 2022 USD ($)	Jan. 31, 2021 USD ($)	Jan. 31, 2022 USD ($) Segment	Jan. 31, 2021 USD ($)	Apr. 30, 2021 USD ($)	Jan. 31, 2020 USD ($)
Organization And Summary Of Significant Accounting Policies [Line Items]
Number of business segments | Segment			7
Number of line of business | Segment			4
Credit loss for available for sales debt securities	$ 0		$ 0			$ 0
Impairment of right of use assets			7,392,000
Impairment of fixed assets			1,915,000
Impairment of long-lived assets		$ 0		$ 0
Impairment of goodwill			0
Impairment of intangible assets			0		$ 0
Performance-related bonus expenses	$ 117,700,000	$ 68,400,000	$ 332,900,000	200,400,000
ASU 2021-01
Organization And Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted	true		true
Change in accounting principle, accounting standards update, adoption date	May 01, 2021		May 01, 2021
Change in accounting principle, accounting standards update, immaterial effect	true		true
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
Leasehold Improvements and Furniture and Fixtures
Organization And Summary Of Significant Accounting Policies [Line Items]
Impairment of fixed assets			$ 1,900,000
Acquired Companies
Organization And Summary Of Significant Accounting Policies [Line Items]
Business acquisitions adjustment, increase in goodwill				$ 2,600,000
Mexican Subsidiary
Organization And Summary Of Significant Accounting Policies [Line Items]
Percentage of Noncontrolling interest in subsidiary	51.00%		51.00%