FAIR VALUE OF FINANCIAL INSTRUMENTS, Schedule of Fair Value of Financial Instruments (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2015	Sep. 30, 2014
Assets [Abstract]
Cash and cash equivalents	$ 338,693	$ 284,155
Other long-term investments	1,855	1,654
Derivative financial instruments	506	100
Total assets	341,054	285,909
Liabilities [Abstract]
Derivative financial instruments	907	270
Total liabilities	907	270
Level 1 [Member]
Assets [Abstract]
Cash and cash equivalents	338,693	284,155
Other long-term investments	1,855	1,654
Derivative financial instruments	0	0
Total assets	340,548	285,809
Liabilities [Abstract]
Derivative financial instruments	0	0
Total liabilities	0	0
Level 2 [Member]
Assets [Abstract]
Cash and cash equivalents	0	0
Other long-term investments	0	0
Derivative financial instruments	506	100
Total assets	506	100
Liabilities [Abstract]
Derivative financial instruments	907	270
Total liabilities	907	270
Level 3 [Member]
Assets [Abstract]
Cash and cash equivalents	0	0
Other long-term investments	0	0
Derivative financial instruments	0	0
Total assets	0	0
Liabilities [Abstract]
Derivative financial instruments	0	0
Total liabilities	$ 0	$ 0