Debt - Additional Information (Details) - USD ($) $ in Thousands			3 Months Ended	9 Months Ended
	Jul. 12, 2019	Nov. 27, 2017	Oct. 31, 2020	Oct. 31, 2020	Apr. 30, 2020
Debt Instrument [Line Items]
Repayment of outstanding principal balance			$ 20,000	$ 20,000
November 2017 Facility | Secured Debt | Wells Fargo Bank
Debt Instrument [Line Items]
Line of credit facility maturity date	Jul. 12, 2022	Nov. 27, 2020
Line of credit facility, finance leases and debt covenant limit	$ 200,000	$ 100,000
November 2017 Facility | Revolving Credit Facility | Secured Debt | Wells Fargo Bank
Debt Instrument [Line Items]
Line of credit facility, termination date		Nov. 27, 2017
Line of credit facility, maximum borrowing capacity	100,000	$ 85,000
Line of credit facility, interest payment terms				Interest on the revolving loans is payable quarterly in arrears with respect to loans based on the prime rate and at the end of an interest period in the case of loans based on the LIBOR rate (or at each three-month interval if the interest period is longer than three months).
Line of credit facility additional amount drawn					$ 30,000
Total debt outstanding with carrying amount			$ 50,000	$ 50,000
Repayment of outstanding principal balance				$ 20,000
November 2017 Facility | Revolving Credit Facility | Secured Debt | Wells Fargo Bank | Prime Rate
Debt Instrument [Line Items]
Line of credit facility, floating interest rate				0.25%
November 2017 Facility | Revolving Credit Facility | Secured Debt | Wells Fargo Bank | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Line of credit facility, floating interest rate				1.00%
November 2017 Facility | Letters of Credit | Secured Debt | Wells Fargo Bank
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity sublimit	$ 45,000	$ 30,000