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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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Equity Incentive Plans - Time-Based Grants (Details)	12 Months Ended
Equity Incentive Plans - Time-Based Grants (Details)	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)		1 year	1 year
Restricted Stock, Time Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	3 years
Share-based Compensation Award, Tranche One \| Restricted Stock, Time Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage (as a percent)	33.33%
Share-based Compensation Award, Tranche Two \| Restricted Stock, Time Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage (as a percent)	33.33%
Share-based Compensation Award, Tranche Three \| Restricted Stock, Time Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage (as a percent)	33.33%