EMPLOYEE BENEFIT PLANS - DEFINED CONTRIBUTION (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Defined Benefit Plan Disclosure [Line Items]
Defined contribution, company match of employee contribution	85.00%
Defined contribution plan, maximum employer contribution by percentage of employee salary	6.00%
Defined contribution plan, cost recognized	$ 5.9	$ 5.5	$ 5.1
Deferred compensation arrangement with individual, employer contribution	$ 2.1	$ 2.4	$ 2.1
NJRHS | Minimum
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer contribution for employees not qualifying for the defined benefit plan	3.50%
NJRHS | Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer contribution for employees not qualifying for the defined benefit plan	4.50%