Investments - Additional Information (Details) - USD ($)	3 Months Ended			6 Months Ended
	Jul. 31, 2023	Apr. 30, 2023	Jul. 31, 2022	Jul. 31, 2023	Jul. 31, 2022	Jan. 31, 2023
Net Investment Income [Line Items]
Unrealized losses for securities in unrealized loss position for less than 12 months	$ 25,200,000			$ 25,200,000		$ 24,800,000
Unrealized losses for securities in unrealized loss position for 12 months or longer	23,300,000			23,300,000		$ 42,000,000
Available-for-sale, realized gain (loss)	0		$ 0	0	$ 0
Purchase of strategic investments				51,000,000	61,550,000
Proceeds from strategic investments				$ 107,244,000	$ 0
Investment in Equity Securities of Private Companies
Net Investment Income [Line Items]
Purchase of strategic investments		$ 51,000,000
Investment in Equity Securities of Public Companies
Net Investment Income [Line Items]
Proceeds from strategic investments	$ 107,200,000