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Marketable Securities - Additional Information (Detail) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jul. 31, 2022
Jul. 31, 2021
Jul. 31, 2022
Jul. 31, 2021
Schedule of Available-for-sale Securities [Line Items]        
Sales and maturities of marketable securities     $ 164,314 $ 148,582
Amortization of discounts and premiums, net $ 1,225 $ 1,398 2,882 2,736
Other (Loss) Income, Net        
Schedule of Available-for-sale Securities [Line Items]        
Net realized gain (loss) $ (222) $ 4 $ (334) $ 4