DERIVATIVE INSTRUMENTS, CREDIT RISK EXPOSURE (Details) (USD $)	9 Months Ended
	Jun. 30, 2011	Sep. 30, 2010
Credit Derivatives [Line Items]
Derivative, Net Liability Position, Aggregate Fair Value	$ 1,300,000	$ 7,400,000
Additional Collateral, Aggregate Fair Value	200,000	5,500,000
Concentration Risk, Credit Risk, Financial Instrument, Maximum Exposure	234,264,000
External Credit Rating, Investment Grade [Member]
Credit Derivatives [Line Items]
Concentration Risk, Credit Risk, Financial Instrument, Maximum Exposure	164,598,000
External Credit Rating, Non Investment Grade [Member]
Credit Derivatives [Line Items]
Concentration Risk, Credit Risk, Financial Instrument, Maximum Exposure	10,567,000
Internally Rated Investment Grade [Member]
Credit Derivatives [Line Items]
Concentration Risk, Credit Risk, Financial Instrument, Maximum Exposure	47,772,000
Internally Rated Noninvestment Grade [Member]
Credit Derivatives [Line Items]
Concentration Risk, Credit Risk, Financial Instrument, Maximum Exposure	$ 11,327,000