INCOME TAXES (Details) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Sep. 30, 2023
Income Tax Contingency [Line Items]
Forecasted effective tax rate	21.70%	22.10%
Revaluation of deferred tax assets and liabilities	$ (1.2)	$ (0.6)
Actual effective tax rate	21.30%	21.90%
ITC carryforward	$ 179.5		$ 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	$ 609.1		$ 631.2
State | Minimum
Income Tax Contingency [Line Items]
Effective term	7 years
State | Maximum
Income Tax Contingency [Line Items]
Effective term	20 years