LONG-TERM DEBT - Long-Term Debt (Details) - USD ($) $ in Thousands  | 
Sep. 30, 2019  | 
Sep. 30, 2018  | 
|---|---|---|
| Debt Instrument [Line Items] | ||
| Long-term debt | $ 940,697 | $ 960,602 | 
| Less current maturities | (42,503) | (31,260) | 
| Total long-term debt and capital lease obligations, excluding current maturities | 898,194 | 929,342 | 
| Senior secured term loan | ||
| Debt Instrument [Line Items] | ||
| Long-term debt | 53,497 | 212,086 | 
| 2025 Senior Notes | ||
| Debt Instrument [Line Items] | ||
| Long-term debt | 296,716 | 296,176 | 
| Notes payable to banks | ||
| Debt Instrument [Line Items] | ||
| Long-term debt | 16,376 | 17,895 | 
| Short-term borrowings | ||
| Debt Instrument [Line Items] | ||
| Long-term debt | 395 | 4,915 | 
| Capital lease obligations | ||
| Debt Instrument [Line Items] | ||
| Long-term debt | 3,631 | 4,569 | 
| Revolving Credit Facility | Line of Credit | ||
| Debt Instrument [Line Items] | ||
| Long-term debt | 476,132 | 322,711 | 
| Securitization facility | ||
| Debt Instrument [Line Items] | ||
| Long-term debt | $ 93,950 | $ 102,250 | 
| X | ||||||||||
- 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. 
  | 
| X | ||||||||||
- Definition Amount of long-term debt and lease obligation, classified as noncurrent. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
  | 
| X | ||||||||||
- Definition Amount of long-term debt and lease obligation, classified as current. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
  | 
| X | ||||||||||
- Definition Amount of long-term debt and lease obligation, including portion classified as current. No definition available. 
  | 
| X | ||||||||||
- Details 
  | 
| X | ||||||||||
- Details 
  | 
| X | ||||||||||
- Details 
  | 
| X | ||||||||||
- Details 
  | 
| X | ||||||||||
- Details 
  | 
| X | ||||||||||
- Details 
  | 
| X | ||||||||||
- Details 
  | 
| X | ||||||||||
- Details 
  |