RETIREMENT PLANS - Benefit Obligations, Plan Assets, Annual Expense, Assumptions and Other Information of the Company's Defined Benefit Pension Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Amounts recognized in the Consolidated Balance Sheets consist of:
Noncurrent assets	$ 50.8	$ 44.0
Noncurrent liabilities	(86.9)	(75.7)
U.S. Plan | Defined Benefit Pension Plan
Change in projected benefit obligation:
Benefit obligation at beginning of year	100.1	110.0
Interest cost	3.5	3.1
Actuarial (gain) loss	11.6	(5.8)
Benefits paid	(7.2)	(7.2)
Projected benefit obligation at end of year	108.0	100.1
Accumulated benefit obligation at end of year	108.0	100.1
Change in plan assets:
Fair value of plan assets at beginning of year	80.7	87.5
Actual return on plan assets	7.6	0.2
Employer contribution	0.2	0.2
Benefits paid	(7.2)	(7.2)
Fair value of plan assets at end of year	81.3	80.7
Unfunded status at end of year	(26.7)	(19.4)
Information for pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	108.0	100.1
Accumulated benefit obligation	108.0	100.1
Fair value of plan assets	81.3	80.7
Amounts recognized in the Consolidated Balance Sheets consist of:
Noncurrent assets	0.0	0.0
Current liabilities	(0.2)	(0.2)
Noncurrent liabilities	(26.5)	(19.2)
Total amount accrued	(26.7)	(19.4)
Amounts recognized in accumulated other comprehensive loss consist of:
Actuarial loss	44.4	37.9
Total amount recognized	44.4	37.9
Total change in other comprehensive loss attributable to:
Pension benefit gain (loss) during the period	(8.0)	1.3
Reclassification of pension benefit losses to net income	1.5	1.5
Prior service cost recognized during the period	0.0	0.0
Foreign currency translation	0.0	0.0
Total change in other comprehensive loss	(6.5)	$ 2.8
Amounts in accumulated other comprehensive loss expected to be recognized as components of net periodic benefit cost in fiscal 2020 are as follows:
Actuarial loss	1.8
Prior service cost	0.0
Amount to be amortized into net periodic benefit cost	$ 1.8
Weighted average assumptions used in development of projected benefit obligation:
Discount rate	2.77%	3.95%
International Plan | Defined Benefit Pension Plan
Change in projected benefit obligation:
Benefit obligation at beginning of year	$ 175.0	$ 190.7
Interest cost	4.0	4.2
Actuarial (gain) loss	21.9	(6.8)
Benefits paid	(7.3)	(8.2)
Other	2.6
Foreign currency translation	(11.0)	(4.9)
Projected benefit obligation at end of year	185.2	175.0
Accumulated benefit obligation at end of year	185.2	175.0
Change in plan assets:
Fair value of plan assets at beginning of year	181.5	181.2
Actual return on plan assets	26.5	6.5
Employer contribution	7.4	7.7
Benefits paid	(7.3)	(8.2)
Foreign currency translation	(11.5)	(5.7)
Fair value of plan assets at end of year	196.6	181.5
Unfunded status at end of year	11.4	6.5
Information for pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	18.1	18.1
Accumulated benefit obligation	18.1	18.1
Fair value of plan assets	0.0	0.0
Amounts recognized in the Consolidated Balance Sheets consist of:
Noncurrent assets	29.5	24.7
Current liabilities	(0.9)	(1.0)
Noncurrent liabilities	(17.2)	(17.2)
Total amount accrued	11.4	6.5
Amounts recognized in accumulated other comprehensive loss consist of:
Actuarial loss	41.8	42.6
Prior service cost	2.5	0.0
Total amount recognized	44.3	42.6
Total change in other comprehensive loss attributable to:
Pension benefit gain (loss) during the period	(2.5)	5.9
Reclassification of pension benefit losses to net income	0.8	1.1
Prior service cost recognized during the period	(2.6)	0.0
Foreign currency translation	2.6	1.2
Total change in other comprehensive loss	(1.7)	$ 8.2
Amounts in accumulated other comprehensive loss expected to be recognized as components of net periodic benefit cost in fiscal 2020 are as follows:
Actuarial loss	0.9
Prior service cost	0.1
Amount to be amortized into net periodic benefit cost	$ 1.0
Weighted average assumptions used in development of projected benefit obligation:
Discount rate	1.60%	2.57%