Stock-Based Compensation - Schedule of Nonvested Performance-Based Units Activity (Details) - Nonvested Performance Share Awards [Member] - $ / shares	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Number of Shares
Nonvested, beginning of year (in shares)	124,750	98,375	116,600
Granted (in shares)	55,325	73,950	57,625
Forfeited (in shares)	(16,615)	(1,600)	(13,977)
Performance adjustments (in shares)	33,941	31,768	57,914
Vested (in shares)	(86,951)	(77,743)	(119,787)
Nonvested, end of year (in shares)	110,450	124,750	98,375
Weighted-Average Per Share Fair Value
Nonvested, beginning of year (in dollars per share)	$ 84.10	$ 89.11	$ 60.71
Granted (in dollars per share)	109.09	74.70	97.79
Forfeited (in dollars per share)	92.88	93.92	71.75
Performance adjustments (in dollars per share)	87.44	71.43	47.50
Vested (in dollars per share)	92.73	76.12	47.55
Nonvested, end of year (in dollars per share)	$ 89.54	$ 84.10	$ 89.11

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

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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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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.

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The net total number of shares (or other type of equity) under an equity-based award plan, other than a stock option plan, that were granted, vested and forfeited during the reporting 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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Weighted average price at which grantees could acquire or could have acquired the underlying shares with respect to any other type of change in shares reserved for issuance.

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