FAIR VALUE MEASUREMENTS (Details) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2020 USD ($) $ / shares
Australian Dollar Forward Contracts | Cost of goods and services
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain reclassified for settled contracts	$ 1,050	$ 994
Designated as Hedging Instrument | Australian Dollar Forward Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, notional amount	8,000	$ 8,000
Contracts weighted average rate price (in dollars per share) | $ / shares		$ 1.63
AOCI currency translation adjustment before tax	849	$ 849
AOCI currency translation adjustment after tax	552	$ 552
Designated as Hedging Instrument | Australian Dollar Forward Contracts | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts duration		30 days
Designated as Hedging Instrument | Australian Dollar Forward Contracts | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts duration		90 days
Not Designated as Hedging Instrument | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts duration		30 days
Not Designated as Hedging Instrument | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts duration		180 days
Not Designated as Hedging Instrument | Canadian Dollar Forward Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, notional amount	$ 3,300	$ 3,300
Derivative, average forward exchange rate	1.41	1.41
Not Designated as Hedging Instrument | British Pound Forward Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, notional amount	$ 4,350	$ 4,350
Derivative, average forward exchange rate	0.81	0.81
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Insurance contracts fair value	$ 3,382	$ 3,382
Fair Value, Inputs, Level 2 | Other Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain (loss) on foreign currency derivative instruments not designated as hedging instruments	271	199
Fair Value, Inputs, Level 2 | Not Designated as Hedging Instrument | Other Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Realized gains (losses)	84	87
Fair Value, Inputs, Level 2 | Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	2,605	2,605
Fair Value, Inputs, Level 2 | Portion at Other than Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	2,236	2,236
Senior notes due 2022 | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible debt, fair value disclosures	139,500	139,500
Senior notes due 2028 | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible debt, fair value disclosures	$ 799,000	$ 799,000