Investments - Additional Information (Details) - USD ($)	3 Months Ended
	Apr. 30, 2023	Apr. 30, 2022	Jan. 31, 2023
Net Investment Income [Line Items]
Unrealized losses for securities in unrealized loss position for less than 12 months	$ 18,900,000		$ 24,800,000
Unrealized losses for securities in unrealized loss position for 12 months or longer	28,600,000		$ 42,000,000
Available-for-sale, realized gain (loss)	0	$ 0
Investment in Equity Securities of Private Companies
Net Investment Income [Line Items]
Purchase of strategic investments	$ 51,000,000