INCOME TAXES - COMPONENTS OF INCOME TAX PROVISION (BENEFIT) (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Current:
Federal	$ 10,933	$ (2,848)	$ (16,023)
State	3,530	4,563	2,470
Deferred:
Federal	7,988	(40,785)	54,965
State	5,833	6,731	11,457
Investment/production tax credits	(66,035)	(21,446)	(34,526)
Income tax (benefit) provision	$ (37,751)	$ (53,785)	$ 18,343

Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.

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