LONG-TERM DEBT - Long-Term Debt (Details) - USD ($) $ in Thousands  | 
Sep. 30, 2017  | 
Sep. 30, 2016  | 
|---|---|---|
| Debt Instrument [Line Items] | ||
| Long-term debt | $ 911,130 | $ 872,554 | 
| Less current maturities | (29,528) | (27,747) | 
| Total long-term debt and capital lease obligations, excluding current maturities | 881,602 | 844,807 | 
| Senior secured term loan | ||
| Debt Instrument [Line Items] | ||
| Long-term debt | 232,479 | 246,449 | 
| Notes payable to banks | ||
| Debt Instrument [Line Items] | ||
| Long-term debt | 21,831 | 5,301 | 
| Short-term borrowings | ||
| Debt Instrument [Line Items] | ||
| Long-term debt | 4,735 | 8,617 | 
| Capital lease obligations | ||
| Debt Instrument [Line Items] | ||
| Long-term debt | 5,134 | 4,187 | 
| Revolving Credit Facility | Line of Credit | ||
| Debt Instrument [Line Items] | ||
| Long-term debt | 551,126 | 608,000 | 
| Securitization facility | ||
| Debt Instrument [Line Items] | ||
| Long-term debt | $ 95,825 | $ 0 | 
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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- Definition Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount of long-term debt and capital leases due within one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount of long-term debt and capital lease obligations including current maturities. No definition available. 
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