Financing Arrangements - Schedule of convertible debt (Details) - USD ($) $ in Thousands	Jul. 31, 2020	May 15, 2020	Jul. 31, 2019
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ (4,246)
Total long-term debt, net of unamortized debt issuance costs	934,209		$ 230,851
3.25% convertible senior notes \| Convertible debt
Debt Instrument [Line Items]
Convertible debt principal amount	168,000		0
Unamortized original issue discount	(38,919)	$ (40,289)	0
Unamortized debt issuance costs	(4,246)	(4,365)	0
Total long-term debt, net of unamortized debt issuance costs	$ 124,835	$ 123,346	$ 0

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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