FAIR VALUE OF FINANCIAL INSTRUMENTS, Schedule of Fair Value of Financial Instruments (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Sep. 30, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 188,354	$ 178,459
Auction rate securities (ARS)	7,966	7,991
Other long-term investments	1,274	1,082
Total	197,594	187,532
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	188,354	178,459
Auction rate securities (ARS)	0	0
Other long-term investments	1,274	1,082
Total	189,628	179,541
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Auction rate securities (ARS)	0	0
Other long-term investments	0	0
Total	0	0
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Auction rate securities (ARS)	7,966	7,991
Other long-term investments	0	0
Total	$ 7,966	$ 7,991