Share-Based Compensation Plans - Restricted Stock and Restricted Stock Units (Details) - Restricted Stock - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Restricted Stock Awards and Units1
Nonvested, beginning of period (in shares)	257,000
Granted (in shares)	101,000
Vested (in shares)	(117,000)
Forfeited (in shares)	(8,000)
Nonvested, end of period (in shares)	233,000	257,000
Weighted Average Grant Date Fair Value
Nonvested, beginning of period (in dollars per share)	$ 104.83
Granted (in dollars per share)	141.70
Vested (in dollars per share)	95.82
Forfeited (in dollars per share)	118.64
Nonvested, end of period (in dollars per share)	126.61	$ 104.83
Weighted-average grant date fair value (in dollars per share)	$ 126.61	$ 104.83	$ 87.36
Total fair value of restricted stock awards and units vested	$ 11,702	$ 7,481	$ 11,060

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

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
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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.

+ References

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-Publisher FASB
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-Topic 718
-SubTopic 10
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-Paragraph 2
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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).

+ References

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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.

+ References

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-Publisher FASB
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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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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

+ References

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-Publisher FASB
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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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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ References

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-Publisher FASB
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- Definition

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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