Debt (Details) - Line of Credit - USD ($)	1 Months Ended		3 Months Ended		9 Months Ended
	Mar. 31, 2021	Jul. 31, 2018	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2021	Oct. 31, 2020
Debt Instrument [Line Items]
Extinguishment of debt	$ 35,000,000
Interest and prepayment fees	$ 1,200,000
2018 Loan | Medium-term Notes
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 45,000,000
Amount borrowed			$ 35,000,000		$ 35,000,000
Issuance costs			1,100,000		1,100,000
Net proceeds from line of credit		$ 33,900,000
Debt maturity (in years)		5 years
Interest expense			$ 0	$ 800,000	$ 1,500,000	$ 2,400,000
2018 Loan | Medium-term Notes | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate		6.55%