FAIR VALUE OF FINANCIAL INSTRUMENTS - Estimated Fair Value of Financial Instruments (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2016	Sep. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total derivative contracts, net	$ (610)	$ (1,794)
Deferred costs and other assets | Foreign currency forwards | Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative assets designated as hedges	59	0
Accrued liabilities | Interest rate swap | Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative liabilities designated as hedges	(669)	(1,312)
Other long-term liabilities | Interest rate swap | Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative liabilities designated as hedges	$ 0	$ (482)