Number of Solar Renewable Energy Certificates

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DERIVATIVE INSTRUMENTS - ADDITIONAL INFORMATION (Details) $ in Thousands, certificate in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023 USD ($) certificate	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) certificate	Jun. 30, 2022 USD ($)	Sep. 30, 2022 USD ($) certificate
Derivative [Line Items]
Derivative, net liability position, aggregate fair value	$ 0		$ 0		$ 161
Treasury Lock \| Interest expense
Derivative [Line Items]
Amount of pre-tax gain (loss) reclassified from OCI into income	$ (342)	$ (341)	$ (1,000)	$ (1,000)
Physical commodity contracts \| Energy Services
Derivative [Line Items]
Number of SRECs (in certificates) \| certificate	1.5		1.5		1.2