DERIVATIVE INSTRUMENTS - CREDIT RISK EXPOSURE (Details) (USD $)	9 Months Ended
	Jun. 30, 2013	Sep. 30, 2012
Credit Risk Exposure [Line Items]
Gross credit exposure	$ 244,804,000
Derivative, net liability position, aggregate fair value	1,200,000	1,600,000
Additional collateral, aggregate fair value	87,000	1,200,000
Investment Grade [Member]
Credit Risk Exposure [Line Items]
Gross credit exposure	199,972,000
Noninvestment Grade [Member]
Credit Risk Exposure [Line Items]
Gross credit exposure	5,679,000
Internally Rated Investment Grade [Member]
Credit Risk Exposure [Line Items]
Gross credit exposure	34,692,000
Internally Rated Noninvestment Grade [Member]
Credit Risk Exposure [Line Items]
Gross credit exposure	$ 4,461,000