STOCK-BASED COMPENSATION, Other (Details) - Stock options - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Stock based awards
Weighted-average remaining life of exercisable stock options	4 years 2 months 12 days
Exercisable stock options, aggregate intrinsic value (in dollars)	$ 16.1
Exercisable Stock Options, Weighted-Average Exercise Price (in dollars per share)	$ 50.87
Number of options vested or expected to vest (in shares)	3,224,548
Options vested or expected to vest, aggregate intrinsic value (in dollars)	$ 16.2
Options vested or expected to vest, weighted-average exercise price (in dollars per share)	$ 56.19
Unrecognized compensation cost (in dollars)	$ 6.6
Period over which unrecognized compensation cost is expected to be recognized	2 years 2 months 12 days
Total intrinsic value of options exercised (in dollars)	$ 13.1	$ 6.3	$ 10.7
Grant date fair value of shares vested (in dollars)	$ 6.7	$ 9.6	$ 8.1

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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Unrecognized cost of unvested options awarded to employees as compensation.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

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