Stock-Based Compensation - Schedule of Stock Options and SSARs Outstanding and Related Activity (Details) - Stock Options - $ / shares	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Shares [Roll Forward]
Outstanding at beginning of period (in shares)	523,754	533,052	593,753
Granted (in shares)	950	30,782	25,230
Exercised (in shares)	(128,921)	(31,450)	(8,411)
Expired (in shares)	0	0	(61,967)
Forfeited (in shares)	(3,318)	(8,630)	(15,553)
Outstanding at end of period (in shares)	392,465	523,754	533,052
Exercisable at end of period (in shares)	354,796	470,501	479,538
Vested or expected to vet in the future (in shares)	391,968	521,362	533,052
Weighted-Average Exercise Price [Roll Forward]
Outstanding at beginning or period (in dollars per share)	$ 14.34	$ 14.26	$ 14.76
Granted (in dollars per share)	10.67	10.23	19.99
Exercised (in dollars per share)	11.01	10.00	7.52
Expired (in dollars per share)	0	0	23.19
Forfeited (in dollars per share)	9.55	10.45	10.46
Outstanding at end of period (in dollars per share)	15.47	14.34	14.26
Exercisable at end of period (in dollars per share)	15.90	14.42	14.03
Vested or expected to vest in the future (in dollars per share)	$ 15.48	$ 14.36	$ 14.26

Share-based Compensation Arrangement by Share-based Payment Award, Outstanding [Roll Forward]

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Share-based Compensation Arrangement by Share-based Payment Award, Outstanding, Weighted Average Exercise Price [Roll Forward]

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- Definition

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 number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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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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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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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Number of share options (or share units) exercised during the current period.

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