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Summary of Significant Accounting Policies - Additional Information (Details) | 12 Months Ended
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Sep. 30, 2019 USD ($) Customer | Sep. 30, 2018 USD ($)
Significant Accounting Policies [Line Items] |  |
Cash and cash equivalents held by foreign subsidiaries and branch offices | $ 7,000,000 |
Minimum credit limit | 30 days |
Extended credit terms for trade receivables | 60 days |
Number of customers affiliated with common parent | Customer | 2 |
Goodwill impairment | $ 0 |
Shipping and handling costs | 46,059,000 | $ 51,913,000
Income tax, Interest or penalties incurred | 0 | 0
Shipping and Handling |  |
Significant Accounting Policies [Line Items] |  |
Shipping and handling costs | 500,000 | 500,000
Customer one |  |
Significant Accounting Policies [Line Items] |  |
Trade account and financing receivable due | $ 6,700,000 | $ 9,000,000
Customer one | Customer Concentration Risk | Sales Revenue, Net |  |
Significant Accounting Policies [Line Items] |  |
Percentage of company revenue | 19.70% | 10.40%
Customer two |  |
Significant Accounting Policies [Line Items] |  |
Trade account and financing receivable due | $ 3,600,000 |
Customer two | Customer Concentration Risk | Sales Revenue, Net |  |
Significant Accounting Policies [Line Items] |  |
Percentage of company revenue | 5.20% |
Customer three |  |
Significant Accounting Policies [Line Items] |  |
Trade account and financing receivable due | $ 8,500,000 |
Customer three | Customer Concentration Risk | Sales Revenue, Net |  |
Significant Accounting Policies [Line Items] |  |
Percentage of company revenue | 20.00% |

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