INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2023
Income Tax Contingency [Line Items]
Forecasted effective tax rate	21.50%	22.50%
Revaluation of deferred tax assets and liabilities	$ (1.2)	$ (0.6)
Actual effective tax rate	20.40%	22.20%
ITC carryforward	$ 185.7		$ 191.2
Effective term	20 years
Operating loss carryforward, valuation allowance	$ 0.7		0.7
State
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 634.2		$ 631.2
State | Minimum
Income Tax Contingency [Line Items]
Effective term	7 years
State | Maximum
Income Tax Contingency [Line Items]
Effective term	20 years