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v3.20.2

Borrowings (Details) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | ---
Sep. 30, 2020 USD ($) item $ / shares | Sep. 30, 2019 USD ($) | Jun. 30, 2020 USD ($) item | Apr. 30, 2019 USD ($) | Feb. 28, 2017 USD ($)
Borrowings |  |  |  |  |
Borrowings outstanding | $ 51,000 |  | $ 59,000 |  |
Revolving Credit Facility |  |  |  |  |
Borrowings |  |  |  |  |
Maximum borrowing capacity |  |  |  | $ 535,000 |
Sub-limit available for letters of credit |  |  |  | 300,000 |
Unused commitment fee (as a percent) | 0.10% |  |  |  |
Amount outstanding under letters of credit | $ 75,400 |  |  |  |
Available credit facility | $ 408,600 |  |  |  |
Revolving Credit Facility | Minimum |  |  |  |  |
Borrowings |  |  |  |  |
Unused commitment fee (as a percent) | 0.10% |  |  |  |
Revolving Credit Facility | Maximum |  |  |  |  |
Borrowings |  |  |  |  |
Increase in the credit agreement's borrowing capacity available under certain circumstances |  |  |  | $ 250,000 |
Unused commitment fee (as a percent) | 0.25% |  |  |  |
Revolving Credit Facility | LIBOR |  |  |  |  |
Borrowings |  |  |  |  |
Interest rate margin (as a percent) | 1.00% |  |  |  |
Revolving Credit Facility | LIBOR | Minimum |  |  |  |  |
Borrowings |  |  |  |  |
Interest rate margin (as a percent) | 1.00% |  |  |  |
Revolving Credit Facility | LIBOR | Maximum |  |  |  |  |
Borrowings |  |  |  |  |
Interest rate margin (as a percent) | 1.75% |  |  |  |
1.25% Convertible Senior Notes Due 2022 |  |  |  |  |
Borrowings |  |  |  |  |
Principal amount | $ 287,500 |  |  |  | $ 287,500
Interest rate (as a percentage) | 1.25% |  |  |  | 1.25%
Conversion ratio | 9.3056 |  |  |  |
Conversion price | $ / shares | $ 107.46 |  |  |  |
Premium on stock price | 38.50% |  |  |  |
Threshold percentage of stock price | 130.00% |  | 130.00% |  |
Number of trading days | item | 20 |  | 20 |  |
Number of consecutive trading days | item | 30 |  | 30 |  |
Principal amount of the notes to be repurchased (as a percentage) | 100.00% |  |  |  |
Liability component of convertible debt | $ 242,400 |  |  |  |
Equity component of convertible debt | 45,100 |  |  |  |
Debt issuance costs | 7,700 |  |  |  |
Debt Component of debt issuance costs | 6,500 |  |  |  |
Equity component of debt issuance costs | 1,200 |  |  |  |
Total interest expense | 3,300 | $ 3,200 |  |  |
Contractual interest expense | 900 | 900 |  |  |
Amortization of debt discount | 2,100 | 2,000 |  |  |
Amortization of debt issuance costs | 300 | $ 300 |  |  |
Unamortized discount | 16,969 |  | $ 19,075 |  |
Unamortized debt issuance costs | $ 2,253 |  | $ 2,547 |  |
Effective interest rate (as a percent) | 4.50% |  |  |  |
Bank lines of credit |  |  |  |  |
Borrowings |  |  |  |  |
Amount outstanding under letters of credit | $ 57,400 |  |  |  |
Available credit facility | $ 14,700 |  |  |  |

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