Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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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Number of shares authorized for issuance under share-based payment arrangement.

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Gross number of share options (or share units) granted during the period.

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Share-based Compensation, Equity Awards Other than Options, Grants, Fair Value

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Stock Award Plans - Additional Information (Details) - USD ($)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized to be reserved (in shares)	5,000,000
Shares available for issuance (in shares)	2,856,502
Contractual term of award (in years)	10 years
Compensation cost for stock options	$ 521,000	$ 0	$ 0
Stock Option Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	356,343	0	0
Unrecognized compensation cost for stock options, net of forfeitures	$ 1,042,000
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instruments other than options, nonvested (in shares)	435,838	460,999	466,681	490,363
Fair market value at date of grant at restricted stock	$ 10,342,436
Compensation cost for stock options	$ 4,188,000	$ 4,259,000	$ 3,659,000
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	3 years
Minimum \| Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	1 year
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	5 years
Maximum \| Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	7 years