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Income Taxes - Additional Information (Details) - USD ($) $ in Thousands | 12 Months Ended
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Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2015
Income Taxes [Line Items] |  |  |
United States statutory tax rate | 35.00% | 35.00% | 35.00%
Cash and cash equivalents held by foreign subsidiaries | $ 7,600 |  |
Temporary difference related to undistributed earnings | 12,800 | $ 13,000 | $ 14,400
Valuation allowance against net deferred tax assets | 20,087 | 7,715 |
United States |  |  |
Income Taxes [Line Items] |  |  |
Net operating loss, carryforwards | $ 24,100 |  |
Net operating loss, carryforwards expiration year | 2037 |  |
Valuation allowance against net deferred tax assets | $ 23,600 | 4,000 |
Canada |  |  |
Income Taxes [Line Items] |  |  |
Net operating loss, carryforwards | $ 18,600 |  |
Net operating loss, carryforwards expiration year | 2033 |  |
Valuation allowance against net deferred tax assets | $ 4,700 | $ 3,700 |
Russia |  |  |
Income Taxes [Line Items] |  |  |
Net operating loss, carryforwards | $ 900 |  |
Net operating loss, carryforwards expiration year | 2026 |  |
United Kingdom |  |  |
Income Taxes [Line Items] |  |  |
Net operating loss, carryforwards | $ 100 |  |

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