Share-Based Compensation - Summary of Performance Share and Restricted Stock Unit Activty (Details) - $ / shares shares in Thousands	12 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Performance shares
Shares / Units (in thousands)
Outstanding shares, beginning balance (in shares)	190
Granted (in shares)	40
Adjustment for performance results achieved (in shares)	64
Vested and issued (in shares)	(139)	(6)	(67)
Forfeited (in shares)	(5)
Outstanding shares, ending balance (in shares)	150	190
Wtd. Avg. Grant Date Share Fair Value
Outstanding, beginning balance (in dollars per share)	$ 112.64
Granted (in dollars per share)	219.04	$ 174.37	$ 87.64
Adjustment for performance results achieved (in dollars per share)	190.46
Vested and issued (in dollars per share)	144.07
Forfeited (in dollars per share)	152.93
Outstanding, ending balance (in dollars per share)	$ 143.94	$ 112.64
Restricted stock and restricted stock units
Shares / Units (in thousands)
Outstanding shares, beginning balance (in shares)	141
Granted (in shares)	47
Vested and issued (in shares)	(38)
Forfeited (in shares)	(4)
Outstanding shares, ending balance (in shares)	146	141
Wtd. Avg. Grant Date Share Fair Value
Outstanding, beginning balance (in dollars per share)	$ 118.87
Granted (in dollars per share)	188.41	$ 138.32	$ 105.38
Vested and issued (in dollars per share)	115.19
Forfeited (in dollars per share)	142.33
Outstanding, ending balance (in dollars per share)	$ 141.35	$ 118.87

Adjusment for performance results achieved.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for the adjustment of target vested shares to the actual performance resutls achieved.

+ References

No definition available.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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