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Trade Accounts and Financing Receivables - Additional Information (Details) - USD ($) $ in Thousands | 1 Months Ended | 3 Months Ended | 9 Months Ended |
--- | --- | --- | --- | ---
Jul. 31, 2019 | Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018 | Sep. 30, 2018
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |
Trade accounts receivable |  | $ 15,789 |  | $ 15,789 |  | $ 15,776
Revenue |  | 12,153 | $ 13,270 | 34,457 | $ 40,454 |
Single Customer |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |
Trade accounts receivable |  | $ 5,400 |  | 5,400 |  |
Revenue |  |  |  | $ 14,600 |  |
Single Customer | Subsequent Event |  |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |  |
Proceeds from trade accounts receivable | $ 1,100 |  |  |  |  |

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