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EMPLOYEE BENEFIT PLANS (Details) - USD ($)
$ in Millions
12 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2017
Compensation Related Costs [Abstract]      
Maximum employer match as percent of employee contribution 50.00%    
Maximum match from employer as a percent of participants' salary 3.00%    
Contributions, net of forfeitures $ 2.4 $ 2.5 $ 2.6
Deferred compensation plan assets 10.4 10.3  
Benefit plan balance $ 5.5 $ 4.2