SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2012	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
ACCOUNTS RECEIVABLE [Abstract]
Accounts receivable, less allowance for doubtful accounts		$ 53,506	$ 52,747
Bad debt expense related to Elpida	3,727
Allowance for doubtful accounts [Roll Forward]
Balance as of September 30, 2011		1,090
Amounts charged to expense		3,771	(18)	(113)
Deductions and adjustments		(104)
Balance as of September 30, 2012		$ 4,757	$ 1,090
Goodwill and Intangible Assets [Abstract]
Number of reporting units to which goodwill and intangible assets have been allocated		4
Maximum [Member]
Goodwill and Intangible Assets [Abstract]
Finite-Lived Intangible Asset, Useful Life		10 years 6 months
Minimum [Member]
Goodwill and Intangible Assets [Abstract]
Finite-Lived Intangible Asset, Useful Life		1 year
Buildings [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life		25 years
Buildings [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life		15 years
Other Machinery and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life		10 years
Other Machinery and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life		3 years
Furniture and fixtures [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life		10 years
Furniture and fixtures [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life		5 years
Technology Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life		5 years
Technology Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life		3 years
Taiwan Semiconductor Manufacturing Co. (TSMC) [Member]
Concentration Risk [Line Items]
Concentration of credit risk by customer (in hundredths)		18.00%	17.00%	18.00%
Percentage of net accounts receivable concentration (in hundredths)		17.10%	12.90%
United Microelectronics Corporation (UMC) [Member]
Concentration Risk [Line Items]
Concentration of credit risk by customer (in hundredths)				11.00%
Samsung [Member]
Concentration Risk [Line Items]
Concentration of credit risk by customer (in hundredths)		13.00%	10.00%
Percentage of net accounts receivable concentration (in hundredths)		12.10%	11.40%