Equity (Schedule of Common Stock Reserved for Future Issuances) (Details) - shares	Jun. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise of outstanding stock options (in shares)	74,044	326,798
Purchases under the employee stock purchase plan (in shares)	818,036
Issuance of stock-based awards under the Equity Plans (in shares)	1,493,848
Purchases under the officer and director share purchase plan (in shares)	88,741
Total reserved (in shares)	4,298,215
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested stock units (in shares)	1,027,992	778,084
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested stock units (in shares)	397,777	328,708
Unvested performance stock units (in shares)	795,554
Maximum payout percentage	200.00%

Common Stock, Stock-based Awards Reserved for Future Issuance

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Employee Stock Purchase Plan (ESPP), Shares Reserved for Future Issuances

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Officer and Director Share Purchase Plan, Shares Reserved for Future Issuances

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Maximum Award Potential

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Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Maximum Award Potential, Percentage

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- Definition

Aggregate number of common shares reserved for future issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29)
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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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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 (c)(2)(i)-(ii)
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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

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-Publisher FASB
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-Topic 718
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