INCOME TAX EXPENSE (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
INCOME TAX EXPENSE
Effective income tax rate	21.30%	14.30%		22.50%	15.90%
Increase (decrease) in valuation allowance (as a percent)					5.10%
Reduction in valuation allowance for excess foreign tax credits		$ 2.8
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Percent			3.30%			1.30%
Effective Income Tax Rate Reconciliation, Deduction, Percent		2.50%
Effective Income Tax Rate Reconciliation, Research Tax Credit And Adjustments For Prior Years' Tax Return To Provision True-Ups, Percent		3.90%			1.20%