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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - SALES TAX ACCOUNTING (Details) - USD ($) $ in Millions | 12 Months Ended
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Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2016
Accounting Policies [Abstract] |  |  |
Sales tax | $ 41.7 | $ 39.4 | $ 31.0
Sales tax, percentage | 6.625% | 6.875% | 7.00%

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- Definition Sales Tax + References No definition available. + Details
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- Definition Sales Tax, Percentage + References No definition available. + Details
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- References No definition available. + Details
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