Financing Arrangements - Schedule of convertible debt (Details) - USD ($) $ in Thousands |
Oct. 31, 2020 |
Jul. 31, 2020 |
May 15, 2020 |
|---|---|---|---|
| Debt Instrument [Line Items] | |||
| Total long-term debt, net of unamortized debt issuance costs | $ 859,892 | $ 934,209 | |
| 3.25% Convertible Senior Notes | Convertible notes | |||
| Debt Instrument [Line Items] | |||
| Loans outstanding | 168,000 | 168,000 | |
| Unamortized original issue discount | (37,282) | (38,919) | $ (40,289) |
| Unamortized debt issuance costs | (4,101) | (4,246) | (4,365) |
| Total long-term debt, net of unamortized debt issuance costs | $ 126,617 | $ 124,835 | $ 123,346 |