SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND RECENT ACCOUNTING PRONOUNCEMENTS (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Deferred income tax assets	$ 5,567	$ 5,840
Accrued expenses, income taxes payable and other current liabilities	100,400	82,983
Other long-term liabilities	18,613	13,046
Retained earnings	$ 472,585	471,673
ASU 2014-09 [Member] | Adjustments Due to ASU 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Deferred income tax assets		261
Accrued expenses, income taxes payable and other current liabilities		(47)
Other long-term liabilities		1,241
Retained earnings		(933)
ASU 2014-09 [Member] | Effect before Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Deferred income tax assets		6,101
Accrued expenses, income taxes payable and other current liabilities		82,936
Other long-term liabilities		14,287
Retained earnings		$ 470,740