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Employee Benefit Plans - Additional Information (Detail) - USD ($)
12 Months Ended
Jan. 31, 2019
Jan. 31, 2018
Jan. 31, 2017
Postemployment Benefits [Abstract]      
Contribution to the ESOP $ 0 $ 0 $ 0
Contributions paid or accrued amounted $ 500,000 $ 500,000 $ 500,000