Employee Benefit Plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Pension benefit obligation balance	$ 0	$ 530,000	$ 1,063,000
Retirement Savings Plan [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Defined contribution plan, cost recognized	$ 1,100,000	$ 1,400,000	$ 1,500,000