INCOME TAXES - COMPONENTS OF INCOME TAX PROVISION (BENEFIT) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Current:
Federal	$ 651	$ (2,164)	$ 10,933
State	1,703	6,763	3,530
Deferred:
Federal	25,030	28,817	4,103
State	6,224	3,400	4,003
Investment/production tax credits	(322)	(322)	(4,129)
Income tax provision	$ 33,286	$ 36,494	$ 18,440