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Marketable Securities - Additional Information (Detail) $ in Thousands	12 Months Ended
	Jan. 31, 2022 USD ($) Security	Jan. 31, 2021 USD ($) Security	Jan. 31, 2020 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Sales and maturities of marketable securities	$ 280,701	$ 396,260	$ 428,508
Amortization of discounts and premiums, net	$ 6,614	$ 1,574	706
Total number of securities with unrealized loss positions within the Company's portfolio | Security	656	184
Interest income
Schedule of Available-for-sale Securities [Line Items]
Net realized gain (loss)	$ 11	$ (419)	$ 39

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Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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